Document:

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                                                                     Exhibit 4.9

                             PARTICIPATION AGREEMENT

PARTICIPATION AGREEMENT ENTERED ON JUNE 14, 2000 INTO BY AND AMONG, ON THE ONE
PART THE FEDERAL GOVERNMENT OF THE UNITED MEXICAN STATES (HEREINAFTER, THE
"FEDERAL GOVERNMENT") THROUGH THE DEPARTMENT OF COMMUNICATIONS AND TRANSPORTS
(HEREINAFTER, "SCT"), NACIONAL FINANCIERA, SOCIEDAD NACIONAL DE CREDITO, TRUST
DIVISION (HEREINAFTER, "NAFIN"), GRUPO AEROPORTUARIO DEL CENTRO NORTE, S.A. DE
C.V. (HEREINAFTER THE "HOLDING COMPANY"), SERVICIOS AEROPORTUARIOS DEL CENTRO
NORTE, S.A. DE C.V. (HEREINAFTER, THE "SERVICES COMPANY"), AEROPUERTO DE
ACAPULCO, S.A. DE C.V., AEROPUERTO DE CHIHUAHUA, S.A. DE C.V., AEROPUERTO DE
CIUDAD JUAREZ, S.A. DE C.V., AEROPUERTO DE CULIACAN, S.A. DE C.V., AEROPUERTO DE
DURANGO, S.A. DE C.V., AEROPUERTO DE MAZATLAN, S.A. DE C.V., AEROPUERTO DE
MONTERREY, S.A. DE C.V., AEROPUERTO DE REYNOSA, S.A. DE C.V., AEROPUERTO DE
TAMPICO, S.A. DE C.V., AEROPUERTO DE TORREON, S.A. DE C.V., AEROPUERTO DE SAN
LUIS POTOSI, S.A. DE C.V., AEROPUERTO DE ZACATECAS, S.A. DE C.V. AND AEROPUERTO
DE ZIHUATANEJO, S.A. DE C.V., (HEREINAFTER JOINTLY REFERRED TO AS THE
"CONCESSION COMPANIES"); AND ON THE OTHER PART OPERADORA MEXICANA DE
AEROPUERTOS, S.A. DE C.V. (HEREINAFTER, THE "STRATEGIC PARTNER"); AS WELL AS
CONSTRUCTORA ICA, S.A. DE C.V., AEROPORTS DE PARIS Y VINCI, S.A. (THE "PARTNERS
OF THE STRATEGIC PARTNER") AS JOINT-AND-SEVERAL OBLIGORS OF THE OBLIGATIONS OF
THE STRATEGIC PARTNER SPECIFICALLY MENTIONED HEREIN FOR EACH OF THEM AND WITH
THE ATTESTATION OF BANCO NACIONAL DE COMERCIO EXTERIOR, SOCIEDAD NACIONAL DE
CREDITO, TRUST DIVISION (HEREINAFTER THE "TRUSTEE") ACCORDING TO THE FOLLOWING
DEFINITIONS, RECITALS AND CLAUSES.

                                   DEFINITIONS

      The terms herein below mentioned shall have the meanings ascribed to each
of them:

Assigned Airports             the Airports of the cities of Acapulco, Chihuahua,
                              Ciudad Juarez, Culiacan, Durango, Mazatlan,
                              Reynosa, Tampico, Torreon and San Luis Potosi, as
                              well as in the municipalities of Apodaca, Nuevo
                              Leon; Calera de Victor Rosales, Zacatecas and
                              Teniente Jose Azueta, Guerrero, as described in
                              the respective Concessions.

Shares                        The shares representing the capital stock of the
                              Holding Company.

Additional Shares             Has the meaning ascribed to them in Section
                              3.4 of this Agreement.

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                                                                   Final Version
                                                         Participation Agreement

Optional Shares               those series "B" shares which shall be kept in the
                              treasury of the Holding Company until the option
                              to subscribe for and pay such shares under the
                              terms of the Option Agreement is exercised or this
                              is terminated and that shall represent 3% (three
                              percent) of the capital stock of the Holding
                              Company, including those shares which are issued
                              pending subscription and payment and which shall
                              be maintained in the treasury.

Indenture                     The minutes of the Extraordinary Shareholders
                              Meeting.

ASA                           Aeropuertos y Servicios Auxiliares. (Airports and
                              Auxiliary Services)

Extraordinary Shareholders    The general extraordinary shareholders meeting of
Meeting                       the Holding Company to be held on this same date
                              which, and pursuant to the Option Agreement shall
                              resolve on the issuance of the Optional Shares.

Change of Control             With respect to any Person ("Person A"), any act
                              (including, without limitation, any consolidation
                              or merger) or a series of acts by virtue of which
                              (i) a third party which is a Person other than the
                              Person A, acquires Control over such Person A; or
                              (ii) if the Person A transfers all or
                              substantially all its assets to any third party,
                              other Person than Person A (for the purposes of
                              this definition, substantially all the assets
                              shall mean any transfer of assets in a single act
                              or in a successive series of acts representing 35%
                              (thirty-five percent) or more of the net worth of
                              the Person A); or (iii) if the shareholders,
                              members, partners or any other holders of rights
                              on the capital of Person A approve any liquidation
                              or dissolution plan of Person A. In addition to
                              the above, a Change of Control in the Strategic
                              Partner means any transfer by the Partners of the
                              Strategic Partner of their participation therein
                              against the provisions of Section 2.4 of this
                              Agreement, and any transfer by the Key Partners of
                              their participation in the Strategic Partner which
                              results in such participation representing, in
                              turn, a direct or indirect participation of less
                              than 7.65% (seven point sixty five percent) in the
                              capital stock of the Holding Company. For the
                              purposes of this definition, no event shall be
                              considered as a Change of Control whenever (i) the
                              same occurs

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                                                                   Final Version
                                                         Participation Agreement

                              In any domestic or foreign company trading shares
                              representing its capital stock in any domestic or
                              foreign stock exchange or which shareholders are
                              mutual fund companies; or (ii) it is a direct
                              consequence of the sale of the share participation
                              in a Person by any government or entity, or
                              political subdivision thereof.

Auditing Committee            The auditing committee of the Holding Company to
                              be incorporated pursuant to the By-laws of the
                              Holding Company and that will have among others,
                              the obligation of surveillance of the compliance
                              by the board of directors and officers of the
                              provisions contained in the By-laws of the Holding
                              Company and the applicable legal provisions.

Nomination and Compensation   The committee provided for in to the By-laws of
Committee                     the Holding Company.

Restructuring Committee       The Restructuring Committee of the
                              Mexican Airport System, created by resolution
                              published in the Federal Official Gazette on
                              February 2, 1996.

Operative Committee           The Operative Committee of the Holding
                              Company to be conformed pursuant to the By-laws of
                              the Holding Company.

Concessions                   The concession certificates as amended, granted by
                              SCT on June 29, 1998 to each of the Concession
                              Companies to operate the Assigned Airports,
                              respectively.

Agreement                     This Participation Agreement.

Technical Assistance
Agreement                     the Technical Assistance and Technology Transfer
                              Agreement executed by the Holding Company, the
                              Concession Companies, the Services Company and the
                              Strategic Partner on the date hereof and attached
                              hereto as Exhibit "E".

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                                                                   Final Version
                                                         Participation Agreement

Assignment Agreement          The rights and obligations assignment agreement
                              executed on November 1, 1998, by and between ASA,
                              as assignor, and each of the Concession Companies
                              as assignees, with respect to the several existing
                              agreements for the operation of the Assigned
                              Airports.

Stock Purchase and Sale       The Stock Purchase and Sale Agreement of the
Agreement                     Shares Package entered on this same date by and
                              among the Federal Government, through SCT, the
                              Federal Treasury, with respect to the endorsement
                              of the certificates representing the Shares
                              Package and the Strategic Partner and the Partners
                              of the Strategic Partner, attached hereto as
                              Exhibit "A".

Movable Property Purchase     the agreement executed on December 1, 1998, by and
and Sale Agreement            among the Federal Government and the Services
                              Company and each of the Concession Companies for
                              the acquisition of the movable property necessary
                              for their operation as well as that of the
                              Assigned Airports and its amendment agreement
                              dated August 24, 1999, attached hereto as Exhibit
                              "H".

Trust Agreement               The Trust Agreement executed on this date, by and
                              among the Strategic Partner, the Trustee and the
                              Holding Company pursuant to Section 2.7 hereof,
                              attached hereto as Exhibit "C".

Option Agreement              The Option Agreement executed on the date of this
                              Agreement by and between the Strategic Partner and
                              the Holding Company and attached hereto as Exhibit
                              "B".

Management Services           The Management Services Provision Agreement
Provision Agreement           executed on June 14, 2000, by and between the
                              Services Company and the Concession Companies
                              attached to the Technical Assistance Agreement as
                              Exhibit "4", through which the former assumed the
                              obligation to provide management services to the
                              latter.

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                                                                   Final Version
                                                         Participation Agreement

Control                       (i) the shareholding by a single Person of more
                              than 35% (thirty-five percent) of the voting
                              capital stock of another Person; (ii) the
                              contractual right of one Person to appoint a
                              majority of the members of the Board of Directors
                              of another Person; or (iii) the right of one
                              Person to cause that, through its vote or through
                              the joint vote of one or more Related Persons, any
                              resolution of the general shareholders' meeting of
                              another Person be approved or objected.

Shareholders Agreement        the Shareholders Agreement entered into on this
                              date by and between Nafin and the Strategic
                              Partner, with the appearance of the Federal
                              Government, of the Holding Company and the Trustee
                              attached herein as Exhibit "D" and which shall
                              become effective on the date on which the
                              Strategic Partner receives from the Federal
                              Government the second Shares Package under the
                              terms of Section 2.6 of the Stock Purchase and
                              Sale Agreement.

Call                          The call for the acquisition of shares
                              representing the capital stock of the Holding
                              Company and the corresponding bidding conditions
                              published in the Federal Official Gazette on
                              December 17, 1999, as amended.

Delegate of the Auditing      Means the member of the Auditing Committee that
Committee                     shall be in charge of overseeing the compliance
                              with the Transaction Documents, in representation
                              of the Airport Group, in terms of the By-laws of
                              the Holding Company.

Transaction Documents         the Stock Purchase and Sale Agreement,
                              the Option Agreement, the Indenture, the Trust
                              Agreement, the Technical Assistance Agreement and
                              the Shareholders Agreement, including the exhibits
                              thereof.

Financial Statements          the financial statements audited as to December
                              31, 1999, that include the financial condition
                              statement, income statement, net worth variation
                              statement and the change in the financial
                              condition statement, as well as the notes to the
                              same, both individual for the Holding Company and
                              its subsidiaries and consolidated for the Holding
                              Company.

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                                                                   Final Version
                                                         Participation Agreement

By-laws of the Holding        the corporate by-laws of the Holding Company
Company                       contained in public instrument number 53703,
                              executed on June 8, 2000 before Attorney-at-Law
                              Luis de Angoitia Becerra, Notary Public No. 109
                              for the Federal District and pending registration
                              with the Public Commercial Registry for the
                              Federal District, attached herein as Exhibit "F",
                              as amended from time to time.

Trust                         The trust constituted by means of the execution of
                              the Trust Agreement under Section 2.7 of this
                              Agreement.

Trustee                       Banco Nacional de Comercio Exterior, Sociedad
                              Nacional de Credito (National Banking
                              Corporation*) as trustee of the Trust Agreement.

Form                          The document delivered to the participants in the
                              Bidding Process that establishes the legal,
                              financial and technical requirements in order for
                              them to evidence their legal, technical,
                              administrative and financial capacity.

Federal Government            The Federal Government of the United Mexican
                              States through the SCT.

Airport Group                 The Holding Company, the Services Company and the
                              Concession Companies.

Process Information           all written information provided to
                              the Strategic Partner during the Bidding Process
                              under the terms of the Call, including that
                              contained in the Data Room (as such term is
                              defined in the Call).

Nafin                         Nacional Financiera, Sociedad Nacional de Credito,
                              (National Banking Corporation) in its capacity as
                              trustee of the trust that as of this date
                              maintains 85% (eighty five percent) of the Shares.

Public Offer                  Has the meaning set forth it in Section 2.3 of
                              this Agreement.

Share Participation           the Shares Package and the Optional Shares

--------------
* Translator's Note- Sociedad Nacional de Credito, National Banking Corporation;
in banking law, a government-controlled bank created as a result of the 1982
nationalization of private banks, which have since been reprivatized. (Javier F.
Becerra, Dictionary of Mexican Legal Terminology)

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                                                                   Final Version
                                                         Participation Agreement

Shares Package                the Series "BB" shares representing 15% (fifteen
                              percent) of the capital stock of the Holding
                              Company {owned by/property of} the Federal
                              Government, which does not include the Optional
                              Shares, and which are acquired on this date by the
                              Strategic Partner, same which are described in the
                              Stock Purchase and Sale Agreement.

Five-Year Waiting Period      Has the meaning set forth in Section 2.4.2 of this
                              Agreement.

Seven-Year Waiting Period     Has the meaning set forth in Section 2.4.1 of this
                              Agreement.

Three-Year Waiting Period     Has the meaning set forth in Section 2.4.1 of this
                              Agreement.

Fifteen-Year Waiting Period   Has the meaning set forth in Section 2.4.1 of this
                              Agreement.

Person                        Any individual or legal entity, association, joint
                              venture, co-investment, trust, or any other entity
                              or organization, including a government, entity or
                              political subdivision or agency thereof, of any
                              nationality.

Related Persons               with respect to any Person, (i) such companies
                              Controlled by, under the same Control, or
                              Controlling the relevant company; (ii) any
                              subsidiary of a Related Person; (iii) such
                              individuals having a consanguinity or civil
                              relationship in direct line up to the fourth
                              degree, in ascending or descending line, with any
                              Person holding 5% (five percent) or more of the
                              shares representing the capital stock of the
                              Person in question or with the Related Persons of
                              such Person. With respect to the Strategic Partner
                              any person with which it has executed an operation
                              agreement to perform the obligations under the
                              Technical Assistance Agreement.

Bidding Process               The bidding process of the Share Participation of
                              the Holding Company made known by SCT by means
                              of the Call.

SCT or Department             The Department of Communications and Transports.

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                                                                   Final Version
                                                         Participation Agreement

Holding Company               Grupo Aeroportuario del Centro Norte, S.A. de C.V.

Services Company              Servicios Aeroportuarios del Centro Norte, S.A. de
                              C.V.

Concession Companies          Aeropuerto de Acapulco, S.A. de C.V., Aeropuerto
                              de Chihuahua, S.A. de C.V., Aeropuerto de Ciudad
                              Juarez, S.A. de C.V., Aeropuerto de Culiacan, S.A.
                              de C.V., Aeropuerto de Durango, S.A. de C.V.,
                              Aeropuerto de Mazatlan, S.A. de C.V., Aeropuerto
                              de Monterrey, S.A. de C.V., Aeropuerto de Reynosa,
                              S.A. de C.V., Aeropuerto de San Luis Potosi, S.A.
                              de C.V., Aeropuerto de Tampico, S.A. de C.V.,
                              Aeropuerto de Torreon, S.A. de C.V., Aeropuerto de
                              Zacatecas, S.A. de C.V. and Aeropuerto de
                              Zihuatanejo, S.A. de C.V.

Strategic Partner             Operadora Mexicana de Aeropuertos, S.A. de C.V.

Key Partners                  the Mexican Partner and the Airport Operator
                              Partner, the shareholders of the Strategic Partner
                              which/who shall jointly keep under the terms of
                              this Agreement at least 51% (fifty-one percent) of
                              the capital stock of the Strategic Partner. Any
                              participation of each the Key Partners greater
                              than 51% (fifty-one percent) in the capital stock
                              of the Strategic Partner shall be considered as a
                              participation of an Investing Partner.

Partners of the Strategic     Both the Key Partners and the Investing Partners
Partner                       of the Strategic Partner.

Investing Partners            Those shareholders that jointly participate in the
                              Strategic Partner, directly or indirectly, with up
                              to 49% (forty-nine percent) of its capital stock.

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                                                                   Final Version
                                                         Participation Agreement

Mexican Partner               Constructoras ICA, S.A. de C.V. a company
                              incorporated in accordance with the laws of the
                              United Mexican States, in which capital stock the
                              foreign investment does not exceeds 49%
                              (forty-nine percent), and that evidenced during
                              the Bidding Process before SCT, experience in the
                              business and labor field in Mexico. The Mexican
                              Partner shall maintain in terms of this Agreement
                              at lest 25.5% (twenty-five point one percent) of
                              the capital stock of the Strategic Partner.

Airport Operator Partner      Aeroports de Paris, a company incorporated under
                              the laws of France, that during the Bidding
                              Process evidenced before SCT capacity and
                              international recognition in the development of
                              airport and commercial activities and that will
                              maintain in terms of this Agreement jointly with
                              the Mexican Partner at least 51% (fifty-one
                              percent) of the capital stock of the Strategic
                              Partner.]

                                    RECITALS

I. The Federal Government states, through SCT, by means of its legal
representative, that:

I.1 On April 7, 1995, by Presidential decree published in the Federal Official
Gazette, the Inter-department De-incorporation Commission (Comision
Intersecretarial de Desincorporacion) was created.

I.2 By several resolutions of the Divestiture Intergovernmental Commission
adopted at its meetings held on August 20 and 25, 1997, October 1 of the same
year, and February 17, 1999, it was agreed to initiate the process of opening to
investment in the Mexican airport system.

I.3 By resolution published in the Federal Official Gazette on February 2, 1996,
the Restructuring Committee of the Mexican Airport System was created, which
purpose is to define the strategy to be followed on general and specific matters
in the different stages of the restructuring process performed by SCT, under the
terms of the Airport Law and other applicable provisions, as well as to make
recommendations and proposals.

I.4 On February 9, 1998, the General Guidelines for the Opening to Investment in
the Mexican Airport System were published in the Federal Official Gazette.

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                                                                   Final Version
                                                         Participation Agreement

I.5 On May 28, 1998, the Holding Company, the Services Company and the
Concession Companies were incorporated.

I.6 On June 29, 1998, SCT granted to each of the Concession Companies the
Concessions for the operation, administration, exploitation and, if applicable,
construction of the Assigned Airports, respectively, copies of which are
attached (without exhibits) to this Agreement as Exhibits "G-1 to G-13".

I.7 On December 17, 1999, the Call was published in the Federal Official
Gazette.

I.8 The Federal Government executed with the Services Company and the Concession
Companies an Movable Property Purchase and Sale Agreement, by virtue of which it
sold and transferred the Movable Property necessary for its operation and the
operation of each Assigned Airport and under such Movable Property Purchase and
Sale Agreement, it is bound by a covenant of warranty of title and to be
responsible for the non-existence of any of the sold property. Therefore, the
Federal Government undertakes such obligations exclusively in favor of the
Services Company and the Concession Company under the terms and conditions set
forth in the Movable Property Purchase and Sale Agreement.

I.9 The Holding Company assumed and capitalized the liabilities that the
Services Company and the Concession Companies had with the Federal Government
for an amount equal to the price of the movable property under the Movable
Property Purchase and Sale Agreement, which amounts to $88'847,444.61 Mexican
Currency (Eighty-Eight Million Eight Hundred Forty-Seven Thousand Four Hundred
Forty-Four Pesos 61/100 Mexican Currency).

I.10 On December 14, 1998, the minimum fixed capital of the Holding Company was
increased in the amount of $77'653,104.00 Mex. CY. (Seventy-Seven Million Six
Hundred and Fifty-Three Thousand One Hundred and Four Pesos 00/100 Mexican
Currency) by means of the capitalization of liabilities in the amount of
$77'653,099.70 Mex. CY. (Seventy-Seven Million Six Hundred and Fifty-Three
Thousand and Ninety-Nine Pesos 70/100 Mexican Currency) in favor of the Federal
Government, as well as the cash contribution that this [the Federal Government]
shall additionally make, and consequently the Holding Company issued 77,653,104
(Seventy-Seven Million Six Hundred and Fifty-Three Thousand One Hundred and
Four) Shares fully paid and non-assessable in favor of the Federal Government.
Additionally, on August 31, 1999, the minimum fixed capital of the Holding
Company was increased in the amount of $11'194,347.00 Mex. Cy (Eleven Million
One Hundred and Ninety-Four Thousand Three Hundred and Forty-Seven Pesos 00/100
Mexican Currency) by means of the capitalization of liabilities in the amount of
$11'194,344.91 (Eleven Million, One Hundred and Ninety-Four Thousand Pesos
00/100 Mexican Currency) in favor of the Federal Government, as well as by means
of a cash contribution that this [the Federal Government] shall additionally
make, and consequently the Holding Company issued 11'194,347 (Eleven Million,
One Hundred and Ninety-Four Thousand Three Hundred and Forty-Seven) fully paid
and non-assessable shares in favor of the Federal Government.

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                                                                   Final Version
                                                         Participation Agreement

I.11 On June 5, 2000, a general extraordinary and ordinary shareholders' meeting
of the Holding Company was held, by virtue of which, the total amendment of its
By-laws was resolved, which By-laws were included in public instrument number
53,704, executed on June 9, 2000 by Attorney-at-Law Luis de Angoitia Becerra,
Notary Public number 109 for the Federal District, which first official
transcript is pending registration with the Public Commercial Registry for the
Federal District.

      On the other hand, on June 2, 2000, the Holding Company executed with all
the Concession Companies a Liability Assumption Agreement by means of which the
Holding Company assumed, on behalf of and in the name of each Concession
Company, the liabilities of their responsibility derived from the utilization of
the Concessions, which amount totals $3,962'404,890.00 Mex. Cy. (Three Thousand,
Nine Hundred and Sixty-Two Million, Four Hundred and Four Thousand Eight Hundred
and Ninety Pesos 00/100 Mexican Currency). Such liability was capitalized in
favor of the Federal Government on June 5, 2000. Additionally, the General
Extraordinary Shareholders' Meeting of the Holding Company held on that same
date approved the capitalization of the retained earnings account, as well as
the updating of the capital stock referred in Note 10 of the Financial
Statements. Derived from the capitalizations approved by shareholders of the
Holding Company, the capital stock was increased in the amount of
$4,230'430,439.00 (Four Thousand Two Thousand and Thirty Million, Four Hundred
and Thirty Thousand Four Hundred and Thirty-Nine Pesos 00/100 Mex. Cy.) issuing
5,670'523,069 (5 Thousand Six Hundred and Seventy Million, Five Hundred and
Twenty-Three Thousand and Sixty-Nine) fully paid-up Shares in favor of the
Federal Government.

I.12 The 100% (one hundred percent) of the capital stock of the Holding Company
amounts to $4,320'277,890.00 Mex. CY. (Four Thousand Three Hundred and Twenty
Million Two Hundred and Seventy-Seven Thousand Eight Hundred and Ninety Pesos
00/100 Mexican Currency), represented by 5,760'370,520 (Five Thousand Seven
Hundred and Sixty Million, Three Hundred and Seventy Thousand Five Hundred and
Twenty) common registered Shares without par value, fully subscribed, paid-in
and outstanding. Additionally, under the terms of the Option Agreement and the
Indenture, the Holding Company, on this same date, shall issue the Optional
Shares that shall be kept in its treasury until the same are subscribed and
paid-in.

I.13 The Shares Package is comprised of 864'055,578 (Eight Hundred and
Sixty-Four Million Fifty-Five Thousand Five Hundred and Seventy-Eight) Series
"BB" common, registered Shares without par value, fully paid and non-assessable
and without any lien or limitation of title thereon.

I.14 On this same date, the Federal Government executed with Nafin, as trustee
in trust number 5111-3, a stock purchase and sale agreement, in order that Nafin
may acquire, in its capacity as trustee, Shares of the Holding Company
representing 85% (eighty-five percent) of its capital stock (except one Share
that Nafin directly obtained from ASA), and therefore, based on Article 46 of
the Organic Law of the Federal Government and Article 75 of the Financial
Institutions Law, as from the date of delivery and transfer of the shares that
Nafin acquired according to that provided for in this recital, the Holding
Company, the Services Company and the Concession Companies shall cease to be a
majority government participation company.

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                                                                   Final Version
                                                         Participation Agreement

I.15 Its representative has sufficient powers and authority to execute this
Agreement pursuant to Article 6, paragraph IX, of the SCT Internal Regulations.

II. Nafin states through its legal representative that:

II.1 It is a national banking corporation, development banking institution,
incorporated under the Financial Institutions Law and its own Organic Law, that
it has legal capacity and patrimony of its own and that under the terms of such
Organic Law, it is authorized to execute this Agreement for the purposes set
forth herein.

II.2 On June 12, 2000 it executed as settlor and trustee an irrevocable trust
agreement in order to promote the investment in the airport industry and promote
the securities market of shares issued by Mexican companies through the public
offering of such Shares it may acquire, and of the share of the Holding Company
property of ASA.

II.3 On this same date, it acquired from the Federal Government, in its capacity
as trustee under the trust mentioned in paragraph II.2 above, Shares of the
Holding Company representing 85% (eighty-five percent) of its capital stock.

II.4 Its representative is duly authorized to execute this Agreement on its
behalf, under the terms of public instrument number 68,440, executed on May 29,
1997, by Attorney-at. Law Cecilio Gonzalez Marquez, Notary Public number 151 for
the Federal District], registered with the Public Commercial Registry for the
Federal District, on July 25, 1997, under commercial folio number 1275.

III. The Holding Company states through its representative that:

III.1 It is a business corporation incorporated under Mexican law, as evidenced
in public instrument number 44,355, dated May 28, 1998, executed by
Attorney-at-Law Emiliano Zubiria Maqueo, Notary Public number 25 for the Federal
District, which first official transcript was recorded on June 25, 1998 with the
Public Commercial Registry for the Federal District under commercial folio
number 238,749.

III.2 It holds 100% (minus one share held by the Federal Government) of the
shares representing the capital stock of each of the Concession Companies and
the Services Company, which are free from any lien or limitation of title.

III.3 Its legal representative has sufficient powers and authority to execute
this Agreement pursuant to public instrument number 52,704 executed before
Attorney-at-Law Luis de Angoitia Becerra, Notary Public number 109 for the
Federal District, which first official transcript was recorded on August 31,
1999 with the Public Commercial Registry for the Federal District under
commercial folio number 238,749.

IV. Each of the Concession Companies states that:

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                                                                   Final Version
                                                         Participation Agreement

IV.1 Aeropuerto de Acapulco, S.A. de C.V. was incorporated by means of public
instrument number 44,369, executed on May 28, 1998, by Attorney-at-Law Emiliano
Zubiria Maqueo, Notary Public number 25 for the Federal District, which first
official transcript was registered with the Public Commercial Registry for the
Federal District, under commercial folio number 238598, on June 25, 1998.

IV.2 Aeropuerto Chihuahua, S.A. de C.V. was incorporated by means of public
instrument number 44,358, executed on May 28, 1998, by Attorney-at-Law Emiliano
Zubiria Maqueo, Notary Public number 25 for the Federal District, which first
official transcript was registered with the Public Commercial Registry for the
Federal District, under commercial folio number 238752, on June 25, 1998.

IV.3 Aeropuerto de Ciudad Juarez, S.A. de C.V. was incorporated by means of
public instrument number 44,357, executed on May 28, 1998, by Attorney-at-Law
Emiliano Zubiria Maqueo, Notary Public number 25 for the Federal District, which
first official transcript was registered with the Public Commercial Registry for
the Federal District, under the commercial folio number 238751.

IV.4 Aeropuerto de Culiacan, S.A. de C.V. was incorporated by means of public
instrument number 44,359, executed on May 28, 1998, by Attorney-at-Law Emiliano
Zubiria Maqueo, Notary Public number 25 for the Federal District, which first
official transcript was registered with the Public Commercial Registry for the
Federal District, under commercial folio number 238753, on June 25, 1998.

IV.5 Aeropuerto de Durango, S.A. de C.V. was incorporated by means of public
instrument number 44,362, executed on May 28, 1998, by Attorney-at-Law Emiliano
Zubiria Maqueo, Notary Public number 25 for the Federal District, which first
official transcript was registered with the Public Commercial Registry for the
Federal District, under commercial folio number 238591, on June 25, 1998.

IV.6 Aeropuerto de Mazatlan, S.A. de C.V. was incorporated by means of public
instrument number 44,360, executed on May 28, 1998, by Attorney-at-Law Emiliano
Zubiria Maqueo, Notary Public number 25 for the Federal District, which first
official transcript was registered with the Public Commercial Registry for the
Federal District, under commercial folio number 23589, on June 25, 1998.

IV.7 Aeropuerto de Monterrey, S.A. de C.V. was incorporated by means of public
instrument number 44,363, executed on May 28, 1998, by Attorney-at-Law Emiliano
Zubiria Maqueo, Notary Public number 25 for the Federal District, which first
official transcript was registered with the Public Commercial Registry for the
Federal District, under commercial folio number 238592, on June 25, 1998.

IV.8 Aeropuerto de Reynosa, S.A. de C.V. was incorporated by means of public
instrument number 44,364, executed on May 28, 1998, by Attorney-at-Law Emiliano
Zubiria Maqueo, Notary Public number 25 for the Federal District, which first
official transcript was registered with the Public Commercial Registry for the
Federal District, under commercial folio number 238593 on June 25, 1998.

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                                                                   Final Version
                                                         Participation Agreement

IV.9 Aeropuerto de San Luis Potosi, S.A. de C.V. was incorporated by means of
public instrument number 44,367, executed on May 28, 1998, by Attorney-at-Law
Emiliano Zubiria Maqueo, Notary Public number 25 for the Federal District, which
first official transcript was registered with the Public Commercial Registry for
the Federal District, under commercial folio number 238751, on June 25, 1998.

IV.10 Aeropuerto de Tampico, S.A. de C.V. was incorporated by means of public
instrument number 44,365, executed on May 28, 1998, by Attorney-at-Law Emiliano
Zubiria Maqueo, Notary Public number 25 for the Federal District, which first
official transcript was registered with the Public Commercial Registry for the
Federal District, under commercial folio number 238594, on June 25, 1998.

IV.11 Aeropuerto de Torreon, S.A. de C.V. was incorporated by means of public
instrument number 44,361, executed on May 28, 1998, by Attorney-at-Law Emiliano
Zubiria Maqueo, Notary Public number 25 for the Federal District, which first
official transcript was registered with the Public Commercial Registry for the
Federal District, under commercial folio number 238590, on June 25, 1998.

IV.12 Aeropuerto de Zacatecas, S.A. de C.V. was incorporated by means of public
instrument number 44,366, executed on May 28, 1998, by Attorney-at-Law Emiliano
Zubiria Maqueo, Notary Public number 25 for the Federal District, which first
official transcript was registered with the Public Commercial Registry for the
Federal District, under commercial folio number 238595, on June 25, 1998.

IV.13 Aeropuerto de Zihuatanejo, S.A. de C.V. was incorporated by means of
public instrument number 44,368, executed on May 28, 1998, by Attorney-at-Law
Emiliano Zubiria Maqueo, Notary Public number 25 for the Federal District, which
first official transcript was registered with the Public Commercial Registry for
the Federal District, under commercial folio number 238597, on June 25, 1998.

IV.14 Each of them holds a Concession for the operation, administration,
exploitation and, as the case may be, construction of the airport corresponding
to them and that are contained in Exhibits "G-1 to G-13" of this Agreement.

IV.15 Their representative has sufficient powers and authority to execute this
Agreement under the terms of the following public instruments all of them
granted before Attorney-at-Law Luis de Angoitia Becerra, Notary Public No. 109
for the Federal District.

      a)    Public instrument number 52,878 dated August 23, 1999 regarding
            Aeropuerto de Acapulco, S.A. de C.V.

      b)    Public instrument number 52,875 dated August 23, 1999 regarding
            Aeropuerto de Chihuahua, S.A. de C.V.

      c)    Public instrument number 52,880 dated August 23, 1999 regarding
            Aeropuerto de Ciudad Juarez, S.A. de C.V.

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                                                                   Final Version
                                                         Participation Agreement

      d)    Public instrument number 52,881 dated August 23, 1999 regarding
            Aeropuerto de Culiacan, S.A. de C.V.

      e)    Public instrument number 52,876 dated August 23, 1999 regarding
            Aeropuerto de Durango, S.A. de C.V.

      f)    Public instrument number 52,867 dated August 20, 1999 regarding
            Aeropuerto de Mazatlan, S.A. de C.V.

      g)    Public instrument number 52,870 dated August 20, 1999 regarding
            Aeropuerto de Monterrey, S.A. de C.V.

      h)    Public instrument number 52,869 dated August 20, 1999 regarding
            Aeropuerto de Reynosa, S.A. de C.V.

      i)    Public instrument number 52,879 dated August 23, 1999 regarding
            Aeropuerto de San Luis Potosi, S.A. de C.V.

      j)    Public instrument number 52,877 dated August 23, 1999 regarding
            Aeropuerto de Tampico, S.A. de C.V.

      k)    Public instrument number 52,873 dated August 20, 1999 regarding
            Aeropuerto de Torreon, S.A. de C.V.

      l)    Public instrument number 52,874 dated August 20, 1999 regarding
            Aeropuerto de Zacatecas, S.A. de C.V.

      m)    Public instrument number 52,868 dated August 20, 1999 regarding
            Aeropuerto de Zihuatanejo, S.A. de C.V.

V. The Services Company states through its legal representative that:

V.1 It was incorporated by means of public instrument number 44,356, executed on
May 28, 1998, by Attorney-at-Law Emiliano Zubiria Maqueo, Notary Public number
25 for the Federal District, which first official transcript was registered on
May 25, 1998 with the Public Commercial Registry for the Federal District under
commercial folio number 238750.

V.2 Its legal representative has sufficient powers and authority to execute this
Agreement under public instrument number 52,872 granted on August 20, 1999
before Attorney-at-Law Luis de Angoitia Becerra, notary public number 109 for
the Federal District.

VI. The Strategic Partner states through its legal representative that

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                                                                   Final Version
                                                         Participation Agreement

VI.1 It is a business corporation duly incorporated under Mexican law by means
of public instrument number 79,502 dated June 9, 2000, granted before
Attorney-at-Law Armando Galvez Perez Aragon, notary public number 103 for the
Federal District, pending registration with the Public Commercial Registry for
the Federal District, and that it has sufficient powers and authority under its
corporate by-laws to execute this Agreement and each of the Transaction
Documents.

VI.2 Its capital stock amounts to $50,000.00 Mex. Cy. (Fifty Thousand Pesos
00/100 Mexican Currency), represented by 50,000 common registered shares, with a
par value of $1.00 Mex. Cy. (One Peso 00/100 Mexican Currency) each, distributed
as follows:

<TABLE>
<CAPTION>
                                    No. of shares
Shareholder                          "A"Series           %
-----------                         -------------     ------
<S>                                 <C>               <C>
Constructoras ICA, S.A. de C.V.        24,500          49.00

Aeroports de Paris                      1,000           2.00

Vinci, S.A.                            24,500          49.00
                                       ------         ------

                  TOTAL:               50,000         100.00
</TABLE>

VI.3 Its legal representative has sufficient powers and authority to execute
this Agreement and each of the Transaction Documents, pursuant to the authority
granted upon him by means of the public instrument referred to in paragraph VI.1
above.

VI.4 By means of official communications numbers GTA00-A108 dated March 27,
2000, issued by the Technical Secretary of the Restructuring Committee of the
Mexican Airport System, their shareholders obtained their authorization as
participants in the Bidding Process.

VI.5 Constructora ICA, S.A. de C.V. was authorized as Mexican Partner by
evidencing sufficient expertise in the business and labor fields in Mexico, and
Aeroports de Paris was also authorized as Airport Operator Partner by evidencing
its ability and international reputation in the performance of airport and
commercial activities. In addition, Vinci, S.A. (formerly called Societe
Generale D'Enterprises) was authorized as Investing Partners of the Strategic
Partner.

VI.6 Their shareholders submitted their bid to acquire the Share Participation
under the terms of the Call and such bid was successful, same which was notified
to them on May 31, 2000 by SCT, through the Chairman of the Restructuring
Committee.

VI.7 It has the necessary technical and financial capacity, as well as
sufficient human resources to comply with its obligations under this Agreement
and each of the exhibits hereto.

                                       16
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                                                                   Final Version
                                                         Participation Agreement

VII. The Partners of the Strategic Partner state through their respective
representatives that:

VII.1 They appear to the execution of this Agreement for the purpose of stating
their consent to their obligations under this instrument and the Transaction
Documents.

VII.2 Their representatives have sufficient powers and authority to execute this
Agreement and the Transaction Documents under the terms of the following public
instruments and that such authority has not been revoked or limited in any
manner whatsoever:

      (a) public instrument number 59,967, executed on September 29, 1998, by
      Attorney-at-Law Jorge Alfredo Dominguez Martinez, Notary Public number 140
      for the Federal District, in which the powers of the legal representative
      of Constructoras ICA, S.A. de C.V. are contained;

      (b) public instrument number 78,528 executed on May 15, 2000, by
      Attorney-at-Law Armando Galvez Perez Aragon, Notary Public number 103 for
      the Federal District, in which the powers of the legal representative of
      Aeroports de Paris are contained;

      (c) public instrument number 78,524 executed on May 15, 2000, by
      Attorney-at-Law Armando Galvez Perez, Notary Public number 108 for the
      Federal District, in which the powers of the legal representative of
      Vinci, S.A. are contained;

VII.3 On this same date, the Strategic Partner has evidenced that it has the
technical capabilities required according to the Call and based on the Operation
Agreement entered into by Aeroports de Paris and the Strategic Partner on the
same date, under which Aeroports de Paris shall provide the Strategic Partner
the technical assistance and shall transfer the technology that is necessary in
order for the latter to comply with its joint-and-several obligation undertaken
under the terms of Section 1.2 of the Technical Assistance Agreement.

VIII. The Trustee states through its representative that:

VIII.1 Under its Organic Law, it is authorized to carry out trust operations
pursuant to its corporate by-laws and the Financial Institutions Law.

VIII.2 It appears to the execution of this Agreement for the purpose of becoming
aware of the scope of its obligations as Trustee under certain Transaction
Documents and to state its agreement therewith.

VIII.3 Its representative is duly authorized to execute this Agreement on its
behalf, as evidenced in public instrument number 32,541, issued on January 14,
1997, by Attorney-at-Law Maximino Garcia Cueto, Notary Public number 14 for the
Federal District, which is duly registered with the Public Commercial Registry
for the Federal District.

                                       17
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                                                                   Final Version
                                                         Participation Agreement

      Based on the above recitals, the parties to this Agreement agree to be
bound by the following

                                     CLAUSES

1.    SUBJECT MATTER

1.1 The subject matter of this Agreement is to set forth the rights and
obligations of the Strategic Partner, the Federal Government, Nafin, the
Trustee, and the Airport Group by virtue of the Bidding Process and the
selection of the Strategic Partner in the administration of the Assigned
Airports under the General Guidelines for the Opening to Investment in the
Mexican Airport System and the Call.

1.2 The parties hereto acknowledge that the determinant reason of the will of
the Federal Government and the Airport Group to execute this Agreement, the
Transaction Documents and any agreements derived therefrom is the practice in
the Mexican business environment, as well as the skills and international
recognition in the performance of airport and commercial activities of the
Strategic Partner and the technical know-how that it may contribute to the
administration of the Assigned Airports.

1.3 Joint-and-several Obligation. The Key Partners execute this Agreement
undertaking a joint-and-several obligation with the Strategic Partner with
respect to the obligations contained in Sections 2.1 and 2.3, and the
obligations specifically set forth in Sections 2.6 and 5.8 below, as well as
8.1.7. In turn, the Investing Partners sign this Agreement assuming a
joint-and-several obligation with the Strategic Partner with respect to the
obligations mentioned in Sections 2.1 and 5.8 below.

1.4 Direct Obligation of the Key Partners. Regardless of that provided for in
the agreements referred to in Recital VII: 3 above, each of the Key Partners
hereby undertakes under this Agreement a direct obligation pursuant to Section
2.4.1 below.

1.5. Direct Obligations of the Strategic Partner and the Airport Operator
Partner. By means of this Agreement, the Strategic Partner and the Airport
Operator Partner, assume the obligations referred to in the second paragraph of
Section 2.6, as well in Section 5.10 below.

2.    OBLIGATIONS OF THE STRATEGIC PARTNER.

2.1 Acquisition of the Shares Package. The Strategic Partner becomes obliged to
acquire the Shares Package and to pay the price of the same to the Federal
Government under the terms of the Stock Purchase and Sale Agreement. For that
purpose, on this date, the Federal Government, the Federal Treasury, the
Strategic Partner, the Key Partners and the Investing Partners execute the Stock
Purchase and Sale Agreement, with the two latter [the Key Partners and the
Investing Partners] being joint-and-several obligors for the payment of the
price of the Shares Package.

                                       18
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                                                                   Final Version
                                                         Participation Agreement

2.2 Acquisition of the Optional Shares. Provided that there is no Event of
Default under this Agreement or under any Transaction Document, the Strategic
Partner shall have the right to subscribe and the obligation to pay the Optional
Shares under the terms provided for in the Option Agreement in the Indenture.

2.3 Participation in the Public Offer of the Shares. The Strategic Partner and
the companies constituting the Airport Group expressly assume the obligation to
assist Nafin so that, not later than in a term of 4 (four) years as from the
date hereof, the Airport Group carries out one or more public offers or other
type of placement among the public investors under the applicable legislation in
each jurisdiction (the "Public Offer"), of at least 36% (thirty-six percent) and
up to the totality of the Shares of the Holding Company owned by Nafin, in its
capacity as trustee, under the terms of the provisions of Section 3.3 below.

      In order for Nafin to be able to fulfill its purpose of placing the Shares
of the Holding Company as stated above, the Strategic Partner as of this moment
becomes obliged to grant Nafin or the Holding Company copy of all the documents
that to such effect are required, including the association documents between
the Partners of the Strategic Partner, as well as to carry out such actions,
agreements and resolutions as may be necessary to attain the public placement of
the Shares, in accordance with the terms, conditions and time schedule
established therefor by Nafin or its underwriters; it shall even agree in the
Trust Agreement that the Trustee to such effects casts its vote for the approval
of such actions and resolutions and provides such information and documentation
as may be reasonably required to obtain the registration of the Holding Company
and the Shares with the National Registry of Securities and Broker-Dealers, as
well as the authorizations from the National Banking and Securities Commission,
the Mexican Stock Exchange (Bolsa Mexicana de Valores, S.A. de C.V.) and, as the
case may be, the corresponding authorities of other countries.

      It shall be understood that the Strategic Partner has complied with its
obligation to assist in the above mentioned Public Offering of shares whenever
(i) it has delivered to the SCT representative appointed for that purpose and to
Nafin all the documents required under the Securities Market Law for the above
purposes, the official communication 11-29 of the National Banking and
Securities Commission as well as any other applicable official communication or
legal provision, and as well as any pursuant to the forms of the competent
authorities of the jurisdictions where the shares representing the capital stock
of the Holding Company are intended to be offered and which may be required in
writing by Nafin or the Federal Government in order to carry out the Public
Offering of the Shares owned by Nafin; and (ii) provide any information as may
be required by the placing agents and collaborate with them; and (iii) the
officers of the Airport Group, the Strategic Partner and the Key Partners that
are required by SCT, attend to the presentation of the terms and conditions of
the Public Offering ("road-shows") and participate in the preparation, promotion
and performance of such meetings.

      The parties agree that no fee or reimbursement of expenses incurred for
assisting Nafin shall correspond to the Strategic Partner in terms of this
section. Additionally, the Strategic Partner accepts that in the event of non
compliance with its obligation in terms of this section, it must cover all the
expenses in which Nafin and the Holding Company may incur with respect to the
Public Offer.]

                                       19
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                                                                   Final Version
                                                         Participation Agreement

2.4 Preservation of a Minimum Equity Interest [participation]. Pursuant to the
provisions of the Call:

      2.4.1 The Key Partners must jointly hold a minimum interest of 51%
      (fifty-one percent) of the Strategic Partner during the term of the this
      Agreement (the "Fifteen-Year Waiting Period"), provided that the Mexican
      Partner must keep a minimum participation of 25.5% (twenty-five point five
      percent) in the capital stock of the Strategic Partner during such
      Fifteen-Year Waiting Period and any additional participation shall be
      considered as an interest of an Investing Partner subject to the Three or
      Five-Year Waiting Periods as set forth below.

      Likewise, the Investing Partners must keep their participation in the
      Strategic Partner for 3 (three) years as of the date on which the first
      public bid of Shares of the Holding Company is carried out, under the
      terms of Section 3.3 of this Agreement (the "Three-Year Waiting Period")
      or for a 5 (five) year period as from the date of execution of this
      Agreement (the "Five-Year Waiting Period), whichever occurs first. Upon
      the expiration of the Fifteen-Year and the Three or Five-Year Waiting
      Periods, as applicable, the Partners of the Strategic Partner may dispose
      of or otherwise transfer without restriction their participation in the
      Strategic Partner.

      2.4.2 The Strategic Partner must hold at least 51% (fifty-one percent) of
      its Equity Interest in the Holding Company acquired according to the Stock
      Purchase and Sale Agreement for a term of 7 (seven) years as of the date
      of execution of this Agreement (the "Seven-Year Waiting Period") and 49%
      (forty-nine percent) of its Equity Interest (including the Technical
      Assistance Shares) during the Three-Year Waiting Period or the Five-Year
      Waiting Period, as the case may be, provided that upon the expiration of
      the Seven-Year Waiting Period, the Strategic Partner may annually transfer
      to third parties up to one eighth of the 51% (fifty-one percent) of its
      Equity Interest in the Holding Company and upon the expiration of the
      Three-Year Waiting Period, or the Five-Year Waiting Period, as the case
      may be, the Strategic Partner may transfer or otherwise dispose of without
      any restrictions the Shares that it holds in the Holding Company in excess
      of such 51% (fifty-one percent) of the Equity Interest.

      2.4.3 Exceptions. The obligations of keeping a minimum participation for
      the Key Partners, the Investing Partners and the Strategic Partner
      contained in Sections 2.4.1. and 2.4.2 above, shall not be applicable
      whenever (i) the participations referred to in such Sections are
      transferred in favor of a Related Person that is not an individual,
      complying with the requirements set forth in the Call and in the Form and
      such circumstance is notified (15) fifteen business days in advance to the
      SCT evidencing compliance with the above mentioned requirements; or (ii)
      the participations referred to in Section 2.4.1 above are transferred with
      the prior authorization in writing from the SCT, between the Partners of
      the Strategic Partner or in favor of any third party provided that it is
      evidenced that such third party complies with the requirements set forth
      in the Call and the Form, as the case may be, and in the event that Nafin
      keeps an interest of less than 51% (fifty-one percent) of the capital
      stock of the Holding Company, in addition to evidencing the requirements
      mentioned above and obtaining the authorization of the SCT, the

                                       20
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                                                                   Final Version
                                                         Participation Agreement

      favorable vote of at least 51% (fifty-one percent) of the capital stock of
      the Holding Company shall be required. In any event mentioned in items (i)
      and (ii) of this paragraph, the purchaser shall bind itself in writing
      with the parties to each of the Transaction Documents to comply with the
      obligations set forth therein prior to the transfer of the corresponding
      participation.

2.5 Participation Limit. Under the By-laws of the Holding Company, Series "A"
and "B" shareholders, individually or jointly with a group of Related Persons,
may keep up to 10% (ten percent) of the Shares representing the capital stock of
the Holding Company, provided that such limitation shall not be applicable to
the Federal Government or to Nafin, as set forth in the By-laws of the Holding
Company. Series "BB" shareholders shall have no limit of participation with
respect to such series, however, the "BB" Series may only represent 15% (fifteen
percent) of the capital stock. In the event that any "BB" Series shareholder
acquires individually or jointly with a group of Related Persons Series "A" or
"B" shares, such shareholders shall have a maximum participation of 20% (twenty
percent) of the capital stock of the Holding Company and may only exercise the
vote of Shares representing up to 10% (ten percent) of such capital stock.

2.6 Execution of the Technical Assistance Agreement. The Strategic Partner
executes, on this same date, the Technical Assistance Agreement with the Holding
Company, the Services Partner and the Concession Companies for the purpose of
establishing and regulating their rights and obligations set forth in Section
2.8.2 below, as well as to set forth the obligation of the Strategic Partner to
provide technical assistance and transfer the necessary technology to the
Airport Group for the operation of the Assigned Airports under the technical
proposal submitted by it in the Bidding Process. The Technical Assistance
Agreement shall become effective on the date in which the Strategic Partner
receives from the Federal Government the second Shares Package under the terms
of the provisions of Section 2.5 of the Stock Purchase and Sale Agreement. The
Key Partners shall be jointly liable with the Strategic Partner with respect to
the obligations contained in Sections 2.2, 3.2, 9.1 and 9.3 of the Technical
Assistance Agreement

      The Strategic Partner and the Airport Operator Partner declare and
guarantee that they have agreed (i) that at the end of the fourth anniversary of
the Technical Assistance Agreement, the Airport Operator Partner shall maintain
a minimum participation of 10% (ten percent) of the capital stock of the
Strategic Partner represented by shares with full voting rights and
non-assessable. The participation in the capital stock of the Strategic Partner
that the Airport Operator Partner acquires in accordance with the provisions of
this paragraph shall be considered as a participation of a Key Partner in the
Strategic Partner and, therefore it shall be subject to the permanency
obligations provided for in Section 2.4.1 of this Agreement; and (ii) that such
obligation may not be modified without the authorization of the SCT.
Notwithstanding the foregoing, if the Strategic Partner and the Airport Operator
Partner agree that the latter maintains a greater participation in the capital
stock of the Strategic Partner, provided that the participation of the Mexican
Partner in the Strategic Partner is not less than 25.5% (twenty-five point five
percent), the authorization of the SCT will not be required, but it shall be
enough that the Strategic Partner gives the SCT a notice in connection with such
acquisitions of additional participation at least 3 (three) businesses days
prior to the date in which the same becomes effective.

                                       21
<PAGE>

                                                                   Final Version
                                                         Participation Agreement

      The Strategic Partner and the Partners of the Strategic Partner accept
that the non-compliance with the provisions of the preceding paragraph will
cause an immediate reduction of 50% (fifty percent) of the compensation provided
for in Section 6.2.1 of the Technical Assistance Agreement.

2.7 Contribution to the Trust. For the purpose of guaranteeing (i) the negative
covenants provided for in Section 2.4 above; (ii) the obligation of the
Strategic Partner not to vote more than 10% (ten percent) of the Shares, and
that the Shares exceeding such percentage are voted in the same manner as the
majority of the Shares into which the capital stock of the Holding Company is
divided; and (iii) the obligations set forth in the Technical Assistance
Agreement, the Strategic Partner, the Holding Company and the Trustee agree to
execute on this same date the Trust Agreement, in which the Trustee shall act as
such, the Strategic Partner shall act as settlor and first beneficiary, and the
Holding Company shall act as second beneficiary. By virtue of such Trust
Agreement, the Strategic Partner shall contribute the Shares Package to the
Trustee, in order that such shares are kept in the Trust. Likewise, the
obligation of the Strategic Partner to contribute to the Trust the Optional
Shares it may acquire shall be set forth.

2.8 Participation in the Administration. The Strategic Partner shall participate
in the administration of the Concession Companies through the following
mechanisms:

      2.8.1 Board of Directors. The Strategic Partner shall participate in the
      board of directors of the Holding Company through the appointment of 3
      (three) permanent members thereof and their alternates, whose appointment
      corresponds to it by reason of its shareholding of Series "BB" of shares
      of the Holding Company. As long as Nafin keeps a participation in the
      capital stock of the Holding Company equivalent to or greater than 50%
      (fifty percent), the Strategic Partner, through the Trustee, shall appoint
      such members, complying with the requirements set forth in the By-laws of
      the Holding Company and the Shareholders Agreement. Once Nafin keeps a
      participation of less than 50% (fifty percent), the 3 (three) members
      shall be appointed by the Series "BB" shareholders at the shareholders'
      meeting pursuant to the By-laws and must meet at least the requirements
      set forth below:

            (i)   be persons of good reputation and with broad business
                  experience, as such requirements are defined by the Nomination
                  and Compensations Committee;

            (ii)  they must have no conflict of interest with the Airport Group;
                  and

            (iii) such persons shall not hold any position in the Airport Group.

      2.8.2 Officers of the Airport Group. The directors appointed by the
      Strategic Partner pursuant to paragraph 2.8.1 above shall be entitled to
      appoint and freely remove 3 (three) of the members of the Operative
      Committee and their alternates, one of which must be the General Director,
      as well as one half of the persons that hold the first level of
      administration reporting to the General Director pursuant to the
      organizational chart attached to this Agreement as Exhibit "J" or in
      accordance with any new administrative chart that in the future is
      approved by the Board of

                                       22
<PAGE>

                                                                   Final Version
                                                         Participation Agreement

      Directors of the Holding Company, provided that such persons shall have,
      at least the responsibilities referred to below in paragraphs 2.8.2.3 to
      2.8.2.5, as applicable, and who must comply with the requirements set
      forth under the Technical Assistance Agreement:

            2.8.2.1 Operative Committee: The Holding Company and the Airport
            Group shall be jointly managed by an Operative Committee which shall
            be formed by 6 (six) members, who may or may not be officers of the
            Services Company. Pursuant to the By-laws of the Holding Company,
            the members of the board of directors of the Holding Company
            appointed by the "BB" series shareholders shall appoint and be
            entitled to remove 3 (three) members that integrate the Operative
            Committee and their alternates, one of which must be the General
            Director, and the other 3 (three) shall be appointed by the majority
            vote of the board of directors of the Holding Company. The General
            Director shall act as Chairman of the Operative Committee and shall
            have a casting vote in the event of a tie;

            2.8.2.2 General Direction: The General Director shall be responsible
            for the management of the Airport Group and of monitoring the good
            operation of the corporate business through the planning,
            programming and organization of the Airport Group. For such
            purposes, he shall also be required to (i) direct the performance of
            the Airport Group programs; (ii) take any steps which tend to carry
            out the functions of the Airport Group, the airport operation and
            the rendering of services, as to provide such services in an
            articulated, congruent and efficient manner, and to maintain the
            closest coordination with the competent authorities; and (iii)
            verify, control and evaluate the performance of the Airport Group;

            2.8.2.3 Senior Position in charge of the Marketing Area: Responsible
            for (i) the preparation and application of marketing programs
            intended to increase the traffic or income of the Assigned Airports,
            as well as to monitor the effectiveness of the marketing practices,
            (ii) coordinate with regional and national agencies and other
            instances, the promotion of the Assigned Airports and the region
            with the airlines, tourist operators, travel agencies and other
            traffic generators; (iii) prepare and carry out advertising
            strategies with mass media and public relations agencies; (iv) the
            relationship with the operative areas with respect to customer
            satisfaction programs and practices; and (v) the creation of a
            marketing team and achieve an adequate transfer of technology,
            reporting in all events directly to the General Direction;

            2.8.2.4 Senior Position in charge of the Commercial Area:
            Responsible for (i) developing commercial activities in the Assigned
            Airports pursuant to the standards offered by the Strategic Partner
            in its technical offer (commercial premises, food and beverages,
            advertising, etc.); (ii) the preparation of global strategies,
            including marketing, commercialization, real estate development,
            advertising and its application thereof throughout the Airport
            Group; (iii) collaborate with the Financial Area and the legal
            department to guarantee that the terms and awarding of the
            commercial agreements

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                        conform to the best commercial and international
                        practice, (iv) the development of coordination programs
                        which retailers/tenants which shall include surveillance
                        and audit procedures; and (v) creating and training the
                        commercialization team by Assigned Airport and
                        throughout the Airport Group, reporting in all events
                        directly to the General Direction;

                        2.8.2.5 Senior Position in charge of the Financial
                        and/or Administrative Area: Responsible for (i) the
                        strategy of improvement, updating and installation of
                        the information systems and the financial reports that
                        may be required; (ii) control of the treasury and
                        investments of the Airport Group; (iii) collaborate with
                        the General Direction and other areas to develop the
                        business plans of the Airport Group, budgets and
                        financial goals; (iv) the relationship with the capital
                        markets and implementing strategies of relationships
                        with investors including the coordination of the
                        registry of the Holding Company in the securities
                        markets where the Public Offer is carried out, if
                        applicable, as well as to coordinate the works of the
                        Holding Company tending to conclude the Public Offer;
                        (v) development and implementation of financing,
                        treasury and comptrollership policies; (vi) formulation
                        and application of acquisition and supplying procedures;
                        and (vii) making sure that the members of this
                        department receive proper training, reporting in all
                        events directly to the General Direction and working
                        closely with the Audit Committee of the Services
                        Company;

                        2.8.2.6 Senior Position in charge of the Area of
                        Operations: Responsible for auditing and supervising
                        and, as the case may be, improving the systems of
                        operation and equipment related to the administration of
                        the terminal, flight and landing area, management of
                        passengers, distribution of taking-off and landing
                        schedules, security and environmental protection; and

                        2.8.2.7 Senior Position in charge of the Area of Human
                        Resources: It shall prepare and be responsible for the
                        labor relationship and maximizing the labor force and
                        the collective labor relationships.

                        The above described positions may be gathered in one
                        officer or person in accordance with the chart attached
                        hereto as Exhibit "J".

2.9 Acknowledgement of the Obligations of the Airport Group. The Strategic
Partner represents that it is aware of the By-laws of the Holding Company, as
well as the by-laws of the Services Company and of the Concession Companies and
therefore, it is acquainted with the mechanisms set forth in such documents for
the decision-making within the Airport Group in connection with its functioning
and operation, which it is obligated to comply with in all of its terms.

      Likewise, the Strategic Partner states that it is aware of the terms and
conditions contained in the Management Services Provision Agreement and that
under this Agreement, it assumes the obligation to provide the Services Company
such technical assistance as may be required pursuant to the Technical
Assistance Agreement, so that the Services Company may comply, in turn, with its
obligations under the Management

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Services Provision Agreement. The foregoing shall not be understood as an
adhesion by the Strategic Partner to the Management Services Provision
Agreement.

      Finally, the Strategic Partner acknowledges that it is fully aware that
the companies that comprise the Airport Group have executed collective bargain
agreements with their employees and have different plans with respect to their
labor relationships as mentioned in Section 6.13 below.

3.    OBLIGATIONS OF THE FEDERAL GOVERNMENT AND NAFIN.

3.1 Sale of the Shares Package. The Federal Government undertakes to sell and
transfer the Shares Package to the Strategic Partner upon the full payment of
the price thereof under the terms set forth in the Stock Purchase and Sale
Agreement, provided that the Strategic Partner shall, upon receipt of the
certificates representing the capital stock of the Airport Group, contribute to
the Trust referred to in Section 2.7 above, the Shares corresponding to the
Shares Package.

3.2 Execution of Agreements. The Federal Government, Nafin and the Trustee,
undertake to execute on this same date (i) the Stock Purchase and Sale
Agreement; (ii) the Trust Agreement; (iii) the Shareholders Agreement, (iv) the
Option Agreement; and (v) to hold the Extraordinary Shareholders Meeting,
respectively, as applicable.

3.3 Public Offer of Shares. Not later than 4 (four) years as of the date of this
Agreement, Nafin undertakes to make one or more public offers or other kind of
stock public placement among the public investor according to the applicable
regulation of each jurisdiction, of the Shares which jointly represent at least
36% (thirty-six percent), as a whole, of the Shares representing the capital
stock of the Holding Company held by Nafin, in the domestic and international
securities markets, only if the market conditions are advantageous to carry out
such sale.

3.4 Purchase Option. In the event that Nafin is not able to carry out the public
offer of at least 36% (thirty-six percent) of the Shares representing the
capital stock of the Holding Company pursuant to Section 3.3 above, Nafin
promises to sell to the Strategic Partner a number of Shares equivalent to 36%
of the capital stock of the Holding Company (the "Additional Shares")
outstanding at that time (without considering such Portion of Shares pending
exercise pursuant to the Option Agreement), under the terms and conditions set
forth below:

      3.4.1. The sale price of the Additional Shares shall be equal to $0.0768
      US Dollars (0.0768 cents of US Dollars) plus interest equal to 5% (five
      percent) per year. The price of the Additional Shares shall be decreased,
      as the case may be, in an amount equivalent to the amount of dividends
      paid in cash or in shares by the Holding Company to Nafin as from the date
      of execution of this Agreement.

      3.4.2. The Strategic Partner shall have a term of 12 (twelve) months as of
      the fourth anniversary of the execution of this Agreement in the event
      that the public offer of shares referred to in Section 3.3 above is not
      performed, to notify Nafin in

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      writing (the "Purchase Notice") of its intention to exercise the purchase
      right set forth in Section 3.4 above, provided that if the Purchase Notice
      is not filed in the aforementioned term such purchase right shall be
      terminated.

      3.4.3. Upon receiving a Purchase Notice, Nafin and the Trustee, in a term
      of 30 (thirty) business days they must (i) hold a shareholders' meeting of
      the Holding Company which purpose is to eliminate the limits of individual
      participation set forth in Article Ten of the By-laws of the Holding
      Company so that the Strategic Partner is able to acquire the Additional
      Shares; (ii) execute an agreement for the modification of the Transaction
      Documents in order to eliminate the limits of individual participation for
      the shareholders of the Holding Company and (iii) obtain all the
      governmental authorizations required for that purpose.

      3.4.4. In the event the Strategic Partner has filed a Purchase Notice with
      Nafin, the Strategic Partner must pay the price in favor of Nafin in
      dollars, currency of the United States of America, or in pesos, at the
      exchange rate of the payment date, as published by Banco de Mexico in the
      Federal Official Gazette in immediately available funds, in the manner
      instructed by Nafin in writing not later than 60 (sixty) business days
      after the date of receipt by Nafin of the Purchase Notice.

      3.4.5. In the event the Strategic Partner acquires the Additional Shares,
      it must execute with Nafin prior to such acquisition, an agreement by
      virtue of which it undertakes the following obligations:

            (i)   In a term of 5 (five) years as from the date of acquisition of
                  the Additional Shares, it shall transfer and place in the
                  domestic and international securities markets through one or
                  several public offers or other type of placements among the
                  public investors pursuant to the applicable legislation in
                  each jurisdiction, the shares representing at least 36%
                  (thirty-six percent) of the capital stock of the Holding
                  Company, in which case Nafin shall be entitled to sell therein
                  or in other public offers, a proportion of Shares equal to
                  those placed by the Strategic Partner; and

            (ii)  Nafin shall be entitled to sell their Shares in the securities
                  market through a public offer at any time as of the execution
                  of this Agreement and notwithstanding the fact that the
                  Strategic Partner has acquired the Additional Shares it shall
                  continue to be bound pursuant to Section 2.3 above, upon
                  Nafin's request. In the event that Nafin places its Shares in
                  the securities market, the Strategic Partner must sell its
                  participation in the Additional Shares in such public offer,
                  provided that the sale price per share (considering any
                  dilution) is equal to or greater than the price of exercise
                  and acquisition of the Additional Shares in dollars at the
                  exchange rate of the date of acquisition thereof plus interest
                  equal to five percent (5%) per year. In the event that
                  existing adequate conditions in the market, the Strategic
                  Partner fails to comply with the obligation set forth in
                  paragraph (i) above and in this paragraph, the Strategic
                  Partner shall contribute the Shares owned by it at that time

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                  representing 36% (thirty-six percent) of the capital stock of
                  the Holding Company in an irrevocable trust where the trustee
                  is instructed to vote such Shares in the same manner as the
                  vote of a majority of the capital stock of the Holding
                  Company, unless the price of the Public Offer is less than the
                  price of acquisition of the Additional Shares in dollars at
                  the exchange rate of the acquisition date thereof plus
                  interest equal to 5% (five percent) per year.

            (iii) In the event that the market conditions do not allow the
                  Strategic Partner to comply with the requirements of paragraph
                  (i) above, the agreement referred to in this Section shall be
                  extended for an indefinite term until the market conditions
                  allow the Strategic Partner or Nafin to comply therewith.

            (iv)  In the event that Nafin wishes to exercise the right mentioned
                  in paragraph (i) above, the Strategic Partner must comply with
                  the obligations contained in Section 2.3 above, determining by
                  common agreement the percentage of shares which may be offered
                  in the securities market. In all events, Nafin and the
                  Strategic Partner shall participate in such offer with the
                  sale of Shares in equal parts.

            (v)   In the event that the Strategic Partner contributes its Shares
                  corresponding to a trust upon the terms of paragraph (ii)
                  above, the Strategic Partner shall have at all the times the
                  right to instruct the trustee to sell such Shares in the
                  securities market and to deliver the proceeds thereof.

      3.4.6. The Shares Package and the Optional Shares, as the case may be,
      shall be kept in Trust to guarantee only the obligations of permanence
      provided for in Sections 2.4. and 2.4.2 above, therefore, amending the
      Trust Agreement in order for the Strategic Partner to become entitled to
      instruct the Trustee as to the manner in which the Shares Package and the
      Optional Shares must be voted as a whole.

3.5 Nafin, in its capacity as trustee, undertakes to comply with the terms of
the stock purchase and sale agreement referred to in statement 1.14 above, as
well as to execute the Shareholders Agreement and to comply with the obligations
contained therein, in particular with those provided for in Section 3.4 above.

4.    OBLIGATIONS OF THE AIRPORT GROUP.

4.1 Optional Shares. Once the Strategic Partner has acquired the Shares Package
and the shareholders of the Holding Company approve said acquisition, the
Holding Company undertakes to issue the Optional Shares and to keep them in its
treasury pending their subscription and payment by the Strategic Partner during
such period and upon such terms as set forth in the Option Agreement. In
addition, it undertakes to keep such Optional Shares representing at all times
3% (three percent) of the outstanding capital stock of the Holding Company after
the issuance thereof. Accordingly, the Holding Company undertakes to execute the
Option Agreement.

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4.2 Technical Assistance Agreement. The Holding Company, the Services Company
and the Concession Companies undertake to execute on this same date the
Technical Assistance Agreement and its exhibits, consequently, they undertake to
carry out any acts necessary for the performance of their obligations
thereunder.

4.3. Public Offer. The Holding Company assumes the obligations set forth in
Section 2.3 above with respect to the assistance to Nafin in the achievement of
the Public Offer in accordance with the terms, conditions and time schedule that
to such effect is established by Nafin or by its underwriters.

4.4. Prohibition of Sale or Assignment. The Holding Company agrees that during
the term of the Option Agreement, it shall not transfer more than 49%
(forty-nine percent) of the capital stock of any of the Concession Companies,
nor shall it allow that the latter assign the Concessions they have to operate
the Assigned Airports. In any event, the Holding Company shall observe the
relevant provisions contained in the By-laws of the Holding Company.

5. COMMITMENTS OF THE STRATEGIC PARTNER. The Strategic Partner guarantees to the
Federal Government and to the Airport Group that upon the execution of this
Agreement and as long as its obligations under the Transaction Documents remain
in full force and affect that:

5.1 Incorporation, Organization and Authority. It is a company duly incorporated
and validly existing as stated in the recitals section of this Agreement and
that its legal representative has sufficient powers and authority to execute the
same and to bind the Strategic Partner as provided for in the Transaction
Documents.

5.2 Validity of the Agreement. This Agreement has been validly executed by the
Strategic Partner and constitutes a valid and binding obligation for the
Strategic Partner, enforceable pursuant to the terms set forth therein.

5.3 Approvals or Notices. Except for the authorizations set forth in Section
7.1.4 of this Agreement, the execution of this Agreement by the Strategic
Partner and the Key Partners and the performance of the transactions
contemplated herein: (i) does not breach or require the consent, approval or
filing of any notice under any applicable law; (ii) except for the Trust, it
shall not result in the creation of any lien on the shares, shall not constitute
a breach or result in the acceleration or early termination of the obligations
of the Strategic Partner or the Key Partners, or in the creation of a lien
pursuant to the corporate by-laws of the Strategic Partner or the corporate
by-laws of the Key Partners, or in the early termination of any mortgage deed,
lease, license agreement, agreement or instrument to which the Strategic Partner
or the Key Partners is a party or by virtue of which the Strategic Partner, the
Key Partners or their assets are affected in such manner that they originate a
default on the obligations of the Strategic Partner or the Key Partners of this
with respect to any Transaction Document, or represent a contingency equivalent
to or greater than 10% (ten percent), jointly or individually of their annual
net sales; or (iii) shall not result in the termination or forfeiture of any
right in the agreements to which the Strategic Partner or the Key Partners are a
party.

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5.4 Taxes. The Strategic Partner and the Key Partners, as of the date of this
Agreement, have filed in due time with the federal, state and municipal
authorities, as well as with any other governmental entities, all necessary tax
returns and made all tax payments that must be made in accordance with the
applicable laws of the jurisdiction of their incorporation and operation and
have paid, or made a provision in their financial statements for, all taxes
derived from their operation, and no issue has arisen or been claimed by the
competent authorities in connection with the above, or if such is the case, they
have initiated the respective actions which are necessary to object the payment
of non-applicable taxes or confirm their compliance with the applicable tax
Laws.

5.5 Litigation. Neither the Strategic Partner nor its Key Partners, as of the
date of this agreement, have any litigation, proceeding, claim or governmental
investigation pending, or litigations brought by any third parties other than
those with respect to which SCT would have been informed during the Bidding
Process, that might affect the continuance of their operations if resolved
adversely against the Strategic Partner or its Key Partners, including any
declaration of bankruptcy or suspension of payments, upon its own request or
upon third parties request, and are in compliance with their payment obligations
with any third parties, or as the case may be, has initiated the corresponding
actions to confirm the compliance with such obligations.

5.6 Financial Statements. The Partners of the Strategic Partner maintain
financial statements that (i) are true, complete and have been prepared
according to the records of the Partners of the Strategic Partner; (ii)
accurately reflect the financial condition, assets and liabilities of the
Partners of the Strategic Partner; (iii) have been prepared pursuant to
generally accepted accounting principles, consistently applied; and (iv) will be
delivered to the Federal Government upon its request. Likewise, the Strategic
Partner undertakes to maintain financial statements that comply with the
provisions of numerals (i) and (ii) above and to deliver them to the Federal
Government upon its request.

5.7 Patents and Trademarks, etc. The Strategic Partner and the Key Partners, as
applicable, have all the patents, registered trademarks, software licenses and
copyrights as may be necessary to render the technical assistance under the
Assistance Agreement. No patent or patent application necessary to render the
technical assistance under such Agreement is involved in a patent infringement
proceeding which might limit its use and license thereof. The Strategic Partner
or the Partners of the Strategic Partner do not use and have not planned to use
or sell any asset that might infringe any trademark, patent, license or right of
any individual or legal entity which might require a license or sublicense under
any such patents, licenses or rights. The Strategic Partner or the Partners of
the Strategic Partner have not received any notice notifying them that they have
infringed any patents, trademarks, licenses, copyrights, industrial secrets or
any other rights related to the Technical Assistance Agreement to the prejudice
of any individual or legal entity.

5.8 Guarantee. The Partners of the Strategic Partner granted a guarantee as part
of the Bidding Process covering the payment of damages and losses in the event
of default in the payment of the price of the Shares Package and any other
consideration in favor of the Federal Government under the Stock Purchase and
Sale Agreement.

5.9 Financial Structure. In terms of the section 9.6.3 of the Call, the
Strategic Partner undertakes to maintain in its financial structure, during a
term of 15 (fifteen) years counted

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as of the execution hereof, a debt level in which the total debt/total assets
ratio is less or equal to 50% (fifty percent)

5.10 Airport Operator Partner's Participation in the Strategic Partner. The
Airport Operator Partner shall have, at the end of the fourth year of the term
of the Technical Assistance Agreement, a minimum participation of 10% (ten
percent) in the capital stock of the Strategic Partner, represented by shares
with full voting rights and non-assessable, which participation shall be subject
to the permanence obligations provided for in Section 2.4.1 of this Agreement;
and such obligation will not be modified without the authorization of the
Department [SCT].

6. COMMITMENTS OF THE AIRPORT GROUP. The Airport Group represents and guarantees
that:

6.1 Organization and Authority. Each of the companies that constitute the
Airport Group is a company duly organized and validly existing under the laws of
the United Mexican States. Furthermore, each of the companies that constitute
the Airport Group has sufficient powers and authority to lease, encumber and use
its assets, as well as to carry out its business as they currently carried them
in the United Mexican States. No dissolution or liquidation proceeding has been
filed by any such companies. The companies of the Airport Group have made
available to the Strategic Partner complete copies of their registry books, the
minutes of their board of directors' and shareholders' meetings, as well as any
other books and records of the company, all of which are adequate and correct.

6.2 Validity of the Agreement. This Agreement has been validly executed by the
companies that comprise the Airport Group and constitutes a valid and binding
obligation for each of them, enforceable under the terms set forth herein.

6.3 Capitalization. Except for the Optional Shares each and all of the Shares
that constitute the capital stock of the companies of the Airport Group have
been duly authorized, fully paid, have been issued in accordance with any
applicable laws and in their issuance there is no breach of any preferential or
similar rights. In addition to such Optional Shares, there are no options,
guarantees, rights, agreements, calls, commitments and offers of any nature
related to the Shares. The shares are free from any lien, interest, restriction
or limitation of title.

6.4 Approvals or Notices. Except for the authorizations referred to in the
recitals of this Agreement, which have been obtained, the execution hereof by
the Airport Group and the transactions contemplated herein shall not (i) breach
or require any consent or approval under any applicable law; (ii) except for the
Trust, result in the creation of any lien on the Shares, constitute a default or
result in the acceleration of the obligations of the companies that comprise the
Airport Group or in the creation of any lien on any portion of the assets of the
companies under the corporate by-laws of the companies that constitute the
Airport Group or any mortgage deed, lease, license agreement, agreement or
instrument to which the companies are a party or by virtue of which any of them
or their assets are affected; or (iii) result in the termination or forfeiture
of any right in the agreements to which they are parties.

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6.5 Financial Statements. The Financial Statements are true and correct,
complete and have been prepared according the terms mentioned in the notes of
the auditors submitted therewith.

6.6 No Amendments. Except as otherwise provided for in Exhibit "I" of this
Agreement, as of the date of preparation of the Financial Statements, as
reflected therein, there has been no adverse change in the assets, liabilities,
financial condition and operations of the Airport Group that may prevent the
companies conforming the same from continuing to operate, except for any changes
arising in the ordinary course of business or such amendments and situations as
have been informed to the Strategic Partner. In the event of any change, as
provided for in this paragraph, to the detriment of the Airport Group, the
Federal Government shall only respond under the terms of Section 10. of the
Stock Purchase and Sale Agreement, in case that the working capital generated
(current assets minus current liabilities) as of the date of the Financial
Statements is not sufficient to compensate for such changes in favor of the
Airport Group.

6.7 Title to Concessions. Each of the Concession Companies holds title of a
Concession for 50 (fifty) years, subject to extension, to administer, operate or
exploit and, as the case may be, build the Assigned Airport corresponding to
each of them, and to use and enjoy the public domain assets referred to in such
Concessions and which are necessary for the operation of the corresponding
Assigned Airports, and such Concessions are not subject to any proceeding that
may affect their validity.

6.8 Title to Assets. Each of the Holding Companies owns the assets described in
the Movable Property Purchase and Sale Agreement which are free and clear of any
lien or limitation of title.

6.9 Taxes. The Airport Group has timely filed with the corresponding federal,
state and municipal authorities, and with any other governmental entities, all
necessary tax returns and made all payments with respect to the companies that
constitute the Airport Group and has paid, caused to be paid, or made a
provision in the Financial Statements, for the payment of all taxes arising from
the operation thereof and no matter has arisen or been claimed by the competent
authorities and therefore, they do not reserve any right or action to claim any
payment or compensation thereof.

6.10 Litigation. The Airport Group has no litigation, proceeding, claim or
governmental investigation pending against the companies that constitute the
Airport Group, or any litigation brought by any third parties, other than those
which have already been informed to the Strategic Partner during the Bidding
Process in the Process Information, which might prevent the continuance of their
operations if resolved adversely against the companies that constitute the
Airport Group. In addition, it has no knowledge that a bankruptcy or suspension
of payments procedure has been initiated, since they are in compliance with all
their monetary obligations.

6.11 Compliance. No notice has been received by the companies that constitute
the Airport Group informing them that they have incurred in any breach to the
Concessions any law, requirement, regulation, injunction, notice, decree, or any
violation, except as otherwise informed to the Strategic Partner during the
Bidding Process, which might

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prevent the Concession Companies from continuing with their operations.
Likewise, none of the Concession Companies has breached their corporate by-laws
or violated any corporate restrictions. The companies that constitute the
Airport Group are not under the presumption of any event of default with respect
to any provisions contained in any agreement, contract or instrument to which
the companies are a party and under which they are bound in such manner that it
prevents that they continue operating or maintaining any of their properties or
assets.

6.12 Compliance with Environmental, Health and Safety Matters. To the knowledge
of the Airport Group:

      6.12.1 Each of the companies that constitutes the Airport Group is in
      compliance with all applicable environmental laws, except as otherwise
      indicated in the audit carried out by the Federal Environmental Protection
      Agency, and must comply with the plan of action determined for it by such
      authority and informed to the Strategic Partner during the Bidding Process
      in the Process Information;

      6.12.2 Any notices, permits, licenses or similar authorizations that
      should have been obtained or filed with any environmental authority in
      connection with the operation of the business have already been obtained
      or, as the case may be, filed, except as otherwise indicated in the audit
      carried out by the Federal Environmental Protection Agency and it must
      comply with the plan of action determined for it by such authority and
      informed to the Strategic Partner during such Bidding Process in the
      Process Information;

      6.12.3 There are no past or pending investigations, proceedings or claims
      against the companies that constitute the Airport Group related to the
      presence, removal or disposal of any hazardous material or due to any
      breach of any applicable environmental law, except as otherwise informed
      to the Strategic Partner during the Bidding Process in the Process
      Information;

      6.12.4 Out of the ordinary course of business, no hazardous material has
      been stored or kept in any building owned by the companies that constitute
      the Airport Group or under their concession, or in any building leased by
      the companies, other than those which were informed to the Strategic
      Partner during the Bidding Process in the Process Information;

      6.12.5 None of the buildings owned, leased or operated by the companies
      that constitute the Airport Group has been used as a waste site or
      contains underground storage tanks, except as otherwise informed to the
      Strategic Partner during the Bidding Process and except for those
      necessary in the ordinary course of their business;

      6.12.6 The companies that constitute the Airport Group have no knowledge
      of any conditions or circumstances that exist or have existed that might
      have caused or imposed any responsibility for such companies with respect
      to any applicable environmental law, except for those informed to the
      Strategic Partner during the Bidding Process in the Process Information;

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      6.12.7 No company constituting the Airport Group has received any notice
      or claim or has knowledge of any factors from which it may be implied that
      they are responsible vis-a-vis any person, as a result of any hazardous
      material originated or stored in any building owned or leased by the
      companies at any time, or that such materials have been unloaded, issued,
      removed or transported from any other source to any building owned or
      leased by the companies that constitute the Airport Group, except as
      otherwise stated to the Strategic Partner during the Bidding Process in
      the Process Information; and

      6.12.8 No condition or circumstance exists or has existed, and none of the
      activities carried out by the companies that constitute the Airport Group
      is occurring or has occurred, that has resulted in an exposure to a
      hazardous material affecting any person or property with respect to which
      the owner of the building or the companies constituting the Airport Group
      might be held responsible in the future for damages and losses resulting
      from such exposure, except as otherwise stated to the Strategic Partner in
      the Information Process during the Bidding Process.

6.13 Labor Matters. None of the companies that constitute the Airport Group has
undergone any strike, lockout by any union or group of workers, except as
otherwise informed to the Strategic Partner during the Bidding Process in the
Process Information. Each of the companies, as of the date hereof, has made all
payments required by the applicable laws or has reserves, as reflected in their
respective financial statements, sufficient for the making of such payments
already due to the National Pension Fund System and the Mexican Institute of
Social Security. The companies have complied with all applicable provisions set
forth in the labor laws for the operation of the companies that constitute the
Airport Group, including provisions concerning the income tax withholding, labor
relationships, fees, equal opportunities, payment of pensions, contributions,
social security and other taxes.

      The companies that constitute the Airport Group have executed collective
bargain agreements with their employees. Likewise, they have executed several
plans with respect to their labor relationships, which include, by way of
enumeration and not by way of limitation, social security plans (birth, marriage
and death) and savings fund plans.

7.    CONDITIONS PRECEDENT.

7.1 Conditions Precedent for the Strategic Partner. The Strategic Partner agrees
that no obligation shall arise for the Federal Government or the Airport Group
under this Agreement and the Transaction Documents, while the Strategic Partner
has not complied with the following conditions precedent:

      7.1.1 Formalization. The Strategic Partner shall have executed the
      Transaction Documents on the date of this Agreement;

      7.1.2 Payment of the Price. The Strategic Partner shall have paid the
      price of the Shares Package on the date established by, and under the
      terms of, the Stock Purchase and Sale Agreement;

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      7.1.3 No Default. No Event of Default imputable to the Strategic Partner
      under this Agreement or the Transaction Documents shall have occurred; and

      7.1.4 Authorizations. The Strategic Partner shall have obtained each and
      all necessary corporate and governmental authorizations, including the
      authorization from the Inter-departmental Commission for the Granting of
      Concessions and Permits under the Airports Law referred to in Article 21
      of such law, and from the Federal Competition Commission, to execute this
      Agreement and any other Transaction Document.

7.2 Conditions Precedent for the Federal Government and the Airport Group. The
Federal Government and the Strategic Partner agree that no obligation shall
arise for the Strategic Partner under this Agreement and the Transaction
Documents, as long as the Federal Government or the Airport Group, as the case
may be, comply with the following conditions precedent:

      7.2.1 Formalization. The Federal Government and the Airport Group shall
      have executed on the same date of this Agreement the applicable
      Transaction Documents;

      7.2.2 No Default. No Event of Default hereunder or under the Transaction
      Documents imputable to the Federal Government or to the Airport Group
      affecting the Strategic Partner shall have occurred;

      7.2.3 Extraordinary Shareholders' Meeting. The Extraordinary Shareholders
      Meeting shall have been held authorizing the issuance of Optional Shares
      for the subsequent subscription and payment thereof.

8.    EVENTS OF DEFAULT.

8.1 Events of Default by the Strategic Partner. In any Event of Default by the
Strategic Partner on its obligations under this Agreement or any of the
Transaction Documents, the Federal Government and the Airport Group shall be
entitled to exercise the remedies set forth in Sections 8.3 and 9. below, as the
case may be. The following are considered as Events of Default by the Strategic
Partner under this Agreement:

      8.1.1 Failure to pay the price of the Shares Package and any other
      consideration to the Federal Government under the Stock Purchase and Sale
      Agreement;

      8.1.2 Failure to comply with any of the obligations under the Technical
      Assistance Agreement once such default is considered as an Event of
      Default pursuant to such agreement and such Technical Assistance Agreement
      has been terminated in advance as a consequence of such Event of Default.
      It shall not be considered that there is an Event of Default for the
      purposes of this Agreement in the event that the termination of the
      Technical Assistance Agreement is pending resolution by an arbitration
      court pursuant to the terms thereof, until such termination has been
      declared by the aforementioned arbitration court;

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                                                         Participation Agreement

      8.1.3 Failure to comply with any of the positive and negative covenants
      under this Agreement or the commitments contained in Section 2.6, as well
      as in Section 5. above;

      8.1.4 Any Change of Control in the Strategic Partner during the Seven-Year
      Waiting Period or any Change of Control in any of the Key Partners of the
      Strategic Partner, except as otherwise previously authorized, in the
      latter case, by SCT pursuant to Section 2.4.3 above, or unless the term
      referred to in Sections 2.4.1 and 2.4.2 above has elapsed;

      8.1.5 Any legal action brought by the Strategic Partner, its Key Partners
      or any third party against the Strategic Partner or the Key Partners,
      resulting in the declaration of bankruptcy or of suspension of payments of
      a court of competent jurisdiction, provided that said declaration is not
      declared unfounded and unlawful by a court of competent jurisdiction for a
      term of 90 (ninety) business days after the date of receipt of the notice
      referred to in Section 8.6 below; or

      8.1.6 The loss at any time by the Strategic Partner or by the Key Partners
      of the Strategic Partner of at least 70% (seventy percent) of its net
      worth, in an act or series of successive acts.

      8.1.7 The breach by the counterpart(s) of the Strategic Partner or by the
      Strategic Partner of any operation agreement or provision of services
      agreement or technical assistance agreement entered into under the terms
      mentioned in Recital VII.3 of this Agreement, in order that the Strategic
      Partner is in a position to comply with the Technical Assistance Agreement
      before the Strategic Partner or the Airport Group, as applicable,
      regardless of the fact that such default is or not declared, as well as
      the early termination of such instrument(s) or modification to the same
      without the prior authorization of the Airport Group or Nafin, as long as
      it holds at least 51% (fifty-one per cent) of the capital stock of the
      Airport Group.

8.2 Grace Period. In order for the events of default set forth in Sections 8.1.3
to 8.1.7 to be deemed as Events of Default of the Strategic Partner, 30 (thirty)
calendar days in the two first cases and 90 (ninety) business days in the three
last cases shall elapse as from the date on which the Federal Government or any
of the companies that constitute the Airport Group has notified such
circumstance to the Strategic Partner under Section 8.4 below, without it having
remedied the respective default. Additionally, the specific rules therein
provided shall apply to the events of default referred to in Sections 2.3 and
2.6 above. Finally, the parties agree that the Event of Default provided for in
Section 8.1.6 shall only be remedied by means of contributions to the capital
stock of the Strategic Partner or of the Key Partner in question, as the case
maybe, sufficient to amortize the losses that exceed 70% (seventy percent) or
its net worth.

8.3 Remedies of the Federal Government and the Airport Group. In any Event of
Default by the Strategic Partner under Sections 8.1 and 8.2 above, the Federal
Government, Nafin and the companies that constitute the Airport Group shall,
separately have the following rights:

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                                                                   Final Version
                                                         Participation Agreement

      8.3.1 In any event of default referred to in Section 8.1.1 above, the
      Federal Government and the companies that constitute the Airport Group
      shall be entitled to terminate this Agreement, and each and all the
      Transaction Documents or to demand, pursuant to Section 9 below, mandatory
      compliance herewith. In the event that the Federal Government decides to
      terminate this Agreement and the other Transaction Documents, the
      Strategic Partner shall forfeit, as contractual penalty arising from its
      failure to pay the price of the Shares Package and in order to repay the
      Federal Government for the damages and losses resulting from such failure,
      with respect to the first installment of the price referred to in the
      Stock Purchase and Sale Agreement, the guarantee mentioned in Section 5.8
      above granted by the Strategic Partner or the Partners of the Strategic
      Partner, as applicable, as part of the Bidding Process, and with respect
      to the second installment of the price under the Stock Purchase and Sale
      Agreement, the equivalent to the first installment of the price of the
      Shares Package.

      8.3.2 In any event of default under Sections 8.1.2 to 8.1.6 as well as
      under Section 8.1.7 above, the provisions of Sections 12.3 and 12.4 of the
      Technical Assistance Agreement shall be applied.

8.4 Procedure. In case that an Event of Default occurs or continues on the part
of the Strategic Partner, Nafin, the Federal Government or the Holding Company,
as the case may be, shall notify the same to the Strategic Partner for the
purposes of Section 8.2 above. In such notice, Nafin, the Federal Government or
the Holding Company, as the case may be, shall indicate to the Strategic Partner
the manner in which they shall exercise their rights with respect to the Event
of Default in question and shall initiate the applicable legal actions under the
Transaction Documents. In the event that Nafin, the Federal Government or the
Holding Company, as the case may be, elects to terminate any legal relationship
pursuant to Section 8.3 above, the same shall be deemed terminated in advance as
from the time of receipt of the above mentioned notice or, as the case may be,
once the terms set forth in Section 8.2 above have elapsed, without prejudice to
the exercise of any other rights under any other Transaction Document.

      For the exercise of their rights under this Agreement, it shall not be
necessary that the Federal Government or the Holding Company obtain any court
order or ruling.

8.5 Events of Default by the Federal Government, the Holding Company and Nafin.

      8.5.1 The following are Events of Default by the Federal Government
      affecting the Strategic Partner:

            8.5.1.1 Failure to comply with the obligation of endorsement and
            delivery of the share certificates corresponding to the Shares
            Package under the Stock Purchase and Sale Agreement;

            8.5.1.2 Failure to comply with their obligations contained in
            Section 3.3 above; and

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                                                                   Final Version
                                                         Participation Agreement

            8.5.1.3 Failure to comply with the commitments contained in Section
            6 above.

      8.5.2 The following are Events of Default by the Holding Company affecting
      the Strategic Partner:

            8.5.2.1 Failure to comply with its affirmative covenants under the
            Option Agreement; or

            8.5.2.2 Failure to comply with its affirmative covenants under the
            Technical Assistance Agreement;

      8.5.3 Failure to comply with its obligations under the Shareholders
      Agreement shall constitute an Event of Default by Nafin in its capacity as
      Trustee.

8.6 Grace Period. In order for the events of default set forth in Section 8.5,
except for that contained in Section 8.5.1.1, to be considered as Events of
Default by the Federal Government, the Holding Company or Nafin, as applicable,
according to the different sections, 30 (thirty) calendar days must elapse as
from the date on which the Strategic Partner or, as the case may be, the Holding
Company or Nafin, as applicable, have notified such Event of Default to, the
Federal Government, to the Holding Company or to Nafin, as applicable, pursuant
to Section 8.8 below. In order for the assumption provided for in Section
8.5.1.1 to be deemed an Event of Default by the Federal Government, 15 (fifteen)
business days must elapse as from the giving of notice by the Strategic Partner
to the Federal Government pursuant to Section 8.8 below.

8.7 Remedies of the Strategic Partner. In any Event of Default by the Federal
Government or the Holding Company under Sections 8.5.1 and 8.5.2 above, the
Strategic Partner shall be entitled to demand specific performance of the
defaulted obligations. In the specific assumptions provided for in Sections
8.5.1.1 and 8.5.1.2 above, the Strategic Partner may demand the early
termination of this Agreement and the Transaction Documents. In the assumption
provided for in Section 8.5.3, the Strategic Partner and the Key Partners shall
be exempted from the obligations under Sections 2.4.1 and 2.4.2 above and
terminate the Technical Assistance Agreement with no liability on their part or
may elect to demand specific performance of the defaulted obligations.

      In no event shall any default by the Federal Government or Nafin under
Section 8.5 above entitle the Strategic Partner to default on its obligations
under this Agreement or the Transaction Documents.

8.8 Procedure. In any Event of Default mentioned in Sections 8.5.1 and 8.5.3
above, the Strategic Partner shall notify such circumstances to the Federal
Government and the Holding Company, as the case may be, indicating the manner in
which it shall exercise its above mentioned rights.

9.    RESOLUTION OF CONTROVERSIES.

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                                                                   Final Version
                                                         Participation Agreement

9.1 Transaction Documents. Any controversy arising in connection with any of the
Transaction Documents must be resolved in accordance with the rules on
resolution of controversies provided for in each of the Transaction Documents
and in the absence of such rules, the controversy shall be submitted to the
jurisdiction of the competent federal courts of the Federal District.

10.   MISCELLANEOUS.

10.1 Notices. Any notice to be delivered by one party to the other under this
Agreement shall be in writing and sent to the other party by certified mail,
return receipt requested, fax or personally delivered and shall be deemed as
made upon its actual receipt by the addressee. All notices shall be sent to the
following domiciles of the parties:

      Strategic Partner:

      Operadora Mexicana de Aeropuertos, S.A. de C.V.
      Viaducto Miguel Aleman No. 81
      Col. Escandon
      11800 Mexico, D.F.

      Attention: Ing. Ruben Lopez Barrera

      Federal Government:

      Secretaria de Comunicaciones y Transportes
      Av. Xola y Universidad
      Col. Narvarte
      Mexico, D.F.

      Attention: Direccion General de Asutnos Juridicos (Legal Department)

      To Airport Group:

      Grupo Aeroportuario del Centro Norte, S.A. de C.V.
      Ave. San Jeronimo 999-11(degree). piso
      Col. San Jeronimo
      64640 Monterrey, Nuevo Leon

      Attention: Director General (General Director)

      Nafin:

      Insurgentes Sur 1971
      Col Guadalupe Inn, C.P. 01020
      Mexico D.F.

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                                                                   Final Version
                                                         Participation Agreement

      Attention: Director Fiduciario (Trustee Director)

      Whenever any of the parties changes its domicile indicated above, it must
notify the same by notice sent to the other parties as provided for in this
Section.

10.2 Term [of the Agreement] and Amendments. This Agreement shall be in force
for a term of 15 (fifteen) years as from its date its execution. In the event
that any of the parties to this Agreement requires any modification thereto, the
following shall be applicable:

      10.2.1 Any early termination of the Agreement (provided that it is not
      caused by a default of the Federal Government) or any amendment to the
      provisions of Section 2.4 during the first 5 (five) years of effectiveness
      of the Agreement or, as long as Nafin holds, directly or indirectly, the
      ownership or control of at least 25% (twenty-five percent) of the capital
      stock of the Holding Company shall require the prior approval of the
      shareholders of the Holding Company and of Nafin, which shall grant it in
      the events where it is duly justified.

      10.2.2 Once such 5 (five)year term has elapsed or in the event that the
      Federal Government holds, directly or indirectly, the ownership or control
      of at least 25% (twenty-five percent) of the capital stock of the Holding
      Company, prior approval from a majority of the members of the Board of
      Directors of the Holding Company shall be required.

      10.2.3 In any of the events provided for in Sections 10.2.1 and 10.2.2
      above, the full compliance with the obligations contained in the
      Concessions must be guaranteed to the Federal Government to its
      satisfaction.

10.3 Confidentiality.

      10.3.1 Each of the parties binds itself to, and, as the case may be, shall
      cause its affiliates, members of the board of directors, officers,
      employees, agents and consultants to bind themselves to keep secret and
      not to disclose or provide to any other person, directly or indirectly, or
      use to the prejudice of the Airport Group or any of the parties, any oral,
      written or other information concerning the Bidding Process, this
      Agreement or the Transaction Documents, the transactions contemplated in
      this Agreement or the Transaction Documents or any other information that
      is confidential or related to the Airport Group, including, without
      limitation, the plans, transactions or results and financial statements
      (jointly, the "Confidential Information"), except to the extent that the
      use of such Confidential Information is necessary to submit or obtain any
      consent or approval required for the performance of the transactions
      contemplated in this Agreement or the Transaction Documents or except to
      the extent that the provision or use of such Confidential Information is
      required by law or is necessary in connection with any legal proceeding.
      Nothing contained in this Agreement shall be construed as the granting of
      a license with respect to such Confidential Information to the receiver
      thereof.

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                                                                   Final Version
                                                         Participation Agreement

      10.3.2 Notwithstanding the provisions of Section 10.3.1 above, any party
      may disclose any information, without any restriction and without any
      obligation to keep such information confidential, provided that (i) the
      disclosure of such information must be made in compliance with any
      applicable law or under the rules or regulations of any stock exchange or
      quotation system, (ii) such information becomes generally available to the
      public by reason other than the disclosure by such party, or (iii) such
      information would have been generally available on a non-confidential
      basis prior to its disclosure by any party.

      10.3.3 Notwithstanding the above, the Federal Government may make public
      announcements on the execution of this Agreement and the Transaction
      Documents and provide the information that, as the case may be, may be
      requested by the competent authorities and the Congress of the Union, if
      applicable, and include such information in the report that it must
      deliver with respect to the Bidding Process. The Strategic Partner may
      make public announcements with respect to the execution of this Agreement
      previously notifying the Department [SCT] in that respect.

      10.3.4 No party may disclose any Confidential Information to any
      consultant or third party advisor unless such consultant or third party
      advisor agrees in writing to be bound by these confidentiality provisions
      and each party and its consultants and third party advisors shall be
      subject to civil penalties and monetary damages if they breach the
      provisions of this Section 10.3.

10.4 Headings. The headings of the sections of this Agreement are included only
for reference purposes and shall not limit or otherwise affect the meaning of
any provision of this Agreement.

10.5 Severability. In the event that one or more of the provisions contained in
this Agreement or the application thereof in any circumstance is declared by any
competent authority invalid, illegal or unenforceable in any aspect or by any
reason, the validity, legality and enforceability of any such provision in any
other aspect and of the remaining provisions of this Agreement, shall not be
limited or affected in any manner whatsoever. Additionally, the parties to this
Agreement agree to use their best efforts to replace such invalid, illegal or
unenforceable provision with a valid, legal and enforceable provision which
shall seek to comply, to the greatest extent possible, with the economic,
business and all other purposes of the invalid or unenforceable provision.

10.6 Successors, Assignees, etc. Except as otherwise provided for in this
Agreement, the parties shall not transfer or assign the rights and obligations
contained under this Agreement or the Transaction Documents without the prior
written consent from the Federal Government and the Holding Company.

10.7 Applicable Law. This Agreement shall be governed by and performed under
Mexican law in federal matters and the laws of the Federal District in local
matters.

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                                                                   Final Version
                                                         Participation Agreement

10.8 Applicable Currency. Except as otherwise expressly provided for in this
Agreement, any reference to any amount of money shall be deemed a reference to
the lawful currency of Mexico, that is, Mexican pesos.

10.9 Counterparts. This Agreement shall be signed in 8 (eight) counterparts,
each of which whenever so signed shall be considered as an original, but all
together shall constitute one and the same instrument.

10.10 Entire Agreement. Except as otherwise specifically provided for herein,
this Agreement, together with the Transaction Documents, supersedes any previous
agreements between the Parties concerning the purpose of this Agreement and such
other documents, and it is the intention of the parties that it is the final
expression and the complete and exclusive statement of their will with respect
to the subject matter of this Agreement and such other instruments.

      In the event of any discrepancy between the provisions of this Agreement
and the Transaction Documents and those contained in the Call and in the General
Guidelines for the Opening to Investment in the Mexican Airport System, the
provisions contained in this Agreement and the Transaction Documents shall
prevail.

10.11 In the event of any inconsistency between any of the Transaction
Documents, the provisions of this Agreement shall rule in the first place, as
well as the provisions of the Stock Purchase and Sale Agreement, the
Shareholders Agreement, the Trust Agreement, the Technical Assistance Agreement
and the Option Agreement in the above mentioned order.

      This Agreement is executed in Mexico City, Federal District, with the
consent of the parties hereto at 12.00 hours on the above mentioned date

OPERADORA MEXICANA DE                       FEDERAL GOVERNMENT, THROUGH
AEROPUERTOS, S.A. DE C.V.                   THE DEPARTMENT OF COMMUNICATIONS
                                            AND TRANSPORTS

       (An illegible signature)                   (An illegible signature)

---------------------------------------     ----------------------------------
By: Ruben Lopez Barrera                     By:   Aaron Dychter Poltolarek
Title: Legal Representative                 Title: Assistant Secretary of
                                                   Transports

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                                                                   Final Version
                                                         Participation Agreement

CONSTRUCTORAS ICA, S.A DE C.V,              NACIONAL FINANCIERA, S.N.C.,
JOINT-AND-SEVERAL OBLIGOR                   TRUST DEPARTMENT
(under the terms of this agreement)

       (An illegible signature)                   (An illegible signature)

---------------------------------------     ----------------------------------
By: Luis F. Zarate Rocha                    By:  Antonio Cardenas Arroyo
Title:  Legal Representative                Title: General Trust Delegate

AEROPORTS DE PARIS                          GRUPO AEROPORTUARIO DEL
JOINT-AND-SEVERAL OBLIGOR                   CENTRO NORTE, S.A. DE C.V.
(under the terms of this Agreement)

       (An illegible signature)                   (An illegible signature)

---------------------------------------     ----------------------------------
By: Jean-Marie Chevallier                   By:   Louis Priede Weston
Title:  Legal Representative                Title: Legal Representative

VINCI, S.A.                                 SERVICIOS AEROPORTUARIOS DEL
JOINT-AND-SEVERAL OBLIGOR                   CENTRO NORTE, S.A. DE C.V.
(under the terms of this agreement)

       (An illegible signature)                   (An illegible signature)

---------------------------------------     ----------------------------------
By: Renaud de Matharel                      By:   Louis Priede Weston
Title: Legal Representative                 Title: Legal Representative

AEROPUERTO DE ACAPULCO,                     AEROPUERTO DE CHIHUAHUA,
S.A. DE C.V.                                S.A. DE C.V.

       (An illegible signature)                   (An illegible signature)

---------------------------------------     ----------------------------------
By: Louis Priede Weston                     By:   Louis Priede Weston
Title: Legal Representative                 Title: Legal Representative

                                       42
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                                                                   Final Version
                                                         Participation Agreement

AEROPUERTO DE CIUDAD JUAREZ,                AEROPUERTO DE CULIACAN,
S.A. DE C.V.                                S.A. DE C.V.

       (An illegible signature)             (An illegible signature)

---------------------------------------     ----------------------------------
By:    Louis Priede Weston                  By:    Louis Priede Weston
Title: Legal Representative                 Title: Legal Representative

AEROPUERTO DE DURANGO,                      AEROPUERTO DE MAZATLAN,
S.A. DE C.V.                                S.A. DE C.V.

       (An illegible signature)                   (An illegible signature)

---------------------------------------     ----------------------------------
By:    Louis Priede Weston                  By:    Louis Priede Weston
Title: Legal Representative                 Title: Legal Representative

AEROPUERTO DE MONTERREY,                    AEROPUERTO DE REYNOSA,
S.A. DE C.V.                                S.A. DE C.V.

       (An illegible signature)                   (An illegible signature)

---------------------------------------     ----------------------------------
By:    Louis Priede Weston                  By:    Louis Priede Weston
Title: Legal Representative                 Title: Legal Representative

AEROPUERTO DE TAMPICO,                      AEROPUERTO DE TORREON,
S.A. DE C.V.                                S.A. DE C.V.

       (An illegible signature)                   (An illegible signature)
---------------------------------------     ----------------------------------

By:    Louis Priede Weston                  By:    Louis Priede Weston
Title: Legal Representative                 Title: Legal Representative

                                       43
<PAGE>

                                                                   Final Version
                                                         Participation Agreement

AEROPUERTO DE SAN LUIS POTOSI,              AEROPUERTO DE ZACATECAS,
S.A. DE C.V.                                S.A. DE C.V.

       (An illegible signature)                   (An illegible signature)

---------------------------------------     ----------------------------------
By:    Louis Priede Weston                  By:    Louis Priede Weston
Title: Legal Representative                 Title: Legal Representative

AEROPUERTO DE ZIHUATANEJO,
S.A. DE C.V.

       (An illegible signature)

---------------------------------------
By:    Louis Priede Weston
Title: Legal Representative

                             WITH THE ATTESTATION OF

                                BANCO NACIONAL DE
                            COMERCIO EXTERIOR, S.N.C.

                         ------------------------------
                            By: Carlos Flores Salinas
                            Title: Trust Delegate

F.\AEROPUERTOS\GACN\CONTRATOS\PARTICIPACIONYANEXOS(INGLES)\FINAL CONTRATO DE
PARTICIPACION (140600)

                                       44<PAGE>

                                                                    Exhibit 4.10

AGREEMENT FOR THE MODIFICATION OF THE PARTICIPATION AGREEMENT

AGREEMENT FOR THE MODIFICATION (THE "AGREEMENT") OF THE PARTICIPATION AGREEMENT
DATED JUNE 14 2000 (THE "PARTICIPATION AGREEMENT") WHICH WAS ENTERED INTO BY AND
AMONG THE FEDERAL GOVERNMENT OF THE UNITED MEXICAN STATES (THE "FEDERAL
GOVERNMENT"), THROUGH THE DEPARTMENT OF COMMUNICATIONS AND TRANSPORTS ("SCT"),
NACIONAL FINANCIERA, S.N.C., DIRECCION FIDUCIARIA [TRUST DIVISION] IN ITS
CAPACITY AS TRUSTEE UNDER TRUST NUMBER 5111-3 ("NAFIN"), GRUPO AEROPORTUARIO DEL
CENTRO NORTE, S.A. DE C.V. (THE CONTROLLLING COMPANY), SERVICIOS AEROPORTUARIOS
DEL CENTRO NORTE, S.A. DE C.V. (THE SERVICES COMPANY), THE CONCESSION COMPANIES,
SERVICIOS DE TECNOLOGIA AEROPORTUARIA, S.A. DE C.V (FORMERLY KNOWN AS OPERADORA
MEXICANA DE AEROPUERTOS S.A. DE C.V. (THE STRATEGIC PARTNER), CONSTRUCTORAS ICA,
S.A. DE C.V. (CURRENTLY AEROINVEST, S.A. DE C.V. ("AEROINVEST")) AND AEROPORTS
DE PARIS ("ADP") WITH THE ATTESTATION OF BANCO NACIONAL DE COMERCIO EXTERIOR,
S.N.C. DIVISION FIDUCIARIA [TRUST DIVISION] (THE TRUSTEE), ENTERED INTO BY AND
AMONG THE FEDERAL GOVERNMENT THROUGH S.C.T., REPRESENTED BY AARON DYCHTER
POLTOLAREK, NAFIN REPRESENTED BY RICARDO RANGEL FERNANDEZ MACGREGOR, THE
CONTROLLING COMPANY REPRESENTED BY RUBEN LOPEZ BARRERA, THE SERVICES COMPANY
REPRESENTED BY RUBEN LOPEZ BARRERA, THE STRATEGIC PARTER REPRESENTED BY LUIS
ZARATE ROCHA, THE TRUSTEE REPRESENTED BY CARLOS FLORES SALINAS, AEROINVEST
REPRESENTED BY ALONSO QUINTANA KAWAGE, ADP REPRESENTED BY NICOLAS CLAUDE, AND
THE CONCESSION COMPANIES, REPRESENTED BY RUBEN LOPEZ BARRERA, AND EMPRESAS ICA,
S.A. DE C.V. (HEREINAFTER "EMICA") REPRESENTED BY JOSE LUIS GUERRERO ALVAREZ
PURSUANT TO THE FOLLOWING DEFINITIONS, BACKGROUND, REPRESENTATIONS AND CLAUSES:

                                   DEFINITIONS

The terms with capital initial defined and used in the Agreement shall have the
meaning attributed to them hereunder, or in the absence thereof, in the
Participation Agreement.

                                   BACKGROUND

      1.    That on June 14 2000 the Participation Agreement was executed with
            the purpose of establishing the rights and obligations between the
            Strategic Partner and the Federal Government, Nafin, the Trustee and
            Grupo Aeroportuario, by virtue of the Bidding Process and the
            selection of the Strategic Partner in the management of the Assigned
            Airports under the General Guidelines for the Opening to Investment
            of the Mexican Airport System and the relevant invitation to bid.

<PAGE>

      2.    On June 14 2005, (i) according to that set forth in Section 3.4.2 of
            the Participation Agreement, the Strategic Partner delivered to
            Nafin the Purchase Notification, expressing in such document its
            intent to exercise the option for the purchase of the Additional
            Shares under the terms of Section 3.4 of the Participation Agreement
            (the "Purchase Option") subject to the conditions set forth in such
            Purchase Notice; and (ii) on grounds of that provided for in Section
            10.6 of the Participation Agreement, the Strategic Partner requested
            authorization to assign in favor of Aeroinvest all the rights and
            obligations relating to the Purchase Option and the Additional
            Shares.

      3.    The Strategic Partner and Aeroinvest have requested SCT the
            modification of Section 3.4.4 of the Participation Agreement, so
            that Aeroinvest may pay the price of the Additional Shares in the
            form that Nafin instructs in writing, no later than on December 30
            2005, consequently deleting the 60 (sixty) day-term originally
            agreed. Further, SCT has expressed that it does not oppose to the
            aforementioned modification.

      4.    According to official communication number 4.612 dated December 21st
            2005, SCT authorized the assignment by the Strategic Partner in
            favor or Aeroinvest of all the rights and obligations relating the
            Purchase Option, according to that set forth in Section 10.6 of the
            Participation Agreement, releasing the Strategic Partner of the
            obligations relating to the acquisition of the Additional Shares,
            including the payment of the price of the same, provided that the
            other obligations on SETA derived from the Transaction Documents and
            the Participation Agreement, including the cooperation obligation
            referred to in Section 2.3 and the obligations referred to in
            Section 3.4.5 of the Participation Agreement, remain in full force
            and effect.

      5.    On December 21 2005, by means of the shareholders meeting of the
            Controlling Company, it was authorized the assignment by the
            Strategic Partner in favor of Aeroinvest of all the rights and
            obligations relating the Purchase Option, according to that set
            forth in section 10.6 of the Participation Agreement mentioned
            before, releasing the Strategic Partner from the obligations
            regarding the acquisition of the Additional Shares, including the
            payment of the price for the same, provided however that the
            remaining obligations on SETA derived from the Transaction Documents
            and of the Participation Agreement including the cooperation
            obligation referred to by Section 2.3 and the obligations referred
            to by Section 3.4.5 of the Participation Agreement remain in full
            force and effect.

      6.    On December 21 2005, Nafin, in attention to the instructions
            received by means of official communications numbers 4.613 and 4.614
            dated December 21 2005 of the SCT, notified the authorization of SCT
            in terms of such official communications in regard to the assignment
            by the Strategic Partner in favor of Aeroinvest of all the rights
            and obligations relating the Purchase Option, releasing the
            Strategic Partner of the obligations relating the acquisition of the
            Additional Shares, including the payment of the price of the same,
            provided the other obligations on SETA derived from the Transaction
            Documents of the Participation Agreement, including the cooperation
            obligation referred to by Section 2.3 and the obligations referred
            to in Section 3.4.5 of the Participation

<PAGE>

            Agreement, remain in full force and effect. A copy of the agreement
            for the assignment of rights and obligations as amended is attached
            hereto as Exhibit "A".

      7.    Aeroinvest has notified SCT in writing the acquisition of 36% of the
            Shares of the Controlling Company, according to that set forth in
            article 23 of the Airports Law. Furthermore, by means of official
            communication 10/1144 dated December 21st 2005, SCT has expressed
            that it does not have any objection whatsoever in connection with
            the aforementioned acquisition.

      8.    By means of resolution dated December 13 2005, the Restructuring
            Committee of the Mexican Airport System, took note and gave its
            favorable opinion to file before Comision Intersecretarial de
            Desincorporacion [The Inter-department De-incorporation Commission]
            the Note "Report on the Exercise of the Purchase Option of 36% of
            the Shares representing the Capital Stock of Grupo Aeroportuario del
            Centro Norte, S.A. de C.V. by Aeroinvest, S.A. de C.V., Mexican
            partner of such group".

      9.    By means of resolution dated December 20 2005, the Inter-department
            De-incorporation Commission created on April 7 1995 by executive
            order published in the Official Gazette of the Federation, took note
            of the report referred to by paragraph 8 above.

      10.   On December 20 2005, and according to that set forth in Section
            10.2.2 of the Participation Agreement, a meeting of the Board of
            Directors of the Controlling Company was held, which approved the
            execution of this Agreement.

      11.   On this same date, Nafin in its capacity as seller and Aeroinvest as
            purchaser, entered into a Purchase and Sale Agreement in regard to
            the Additional Shares (the "Purchase and Sale Agreement") subject to
            the condition precedent of executing this Agreement and the other
            documents referred to in section 5 of the Purchase and Sale
            Agreement.

                                 REPRESENTATIONS

I. The Federal Government by means of SCT through its legal representative
represents that:

      1.    It recognizes to have executed the Participation Agreement on June
            14 2000.

      2.    It has full knowledge of the Purchase Notice presented by the
            Strategic Partner to Nafin and it recognized the need of modifying
            the Participation Agreement, in order to delete the individual
            participation limits of the Controlling Company in terms of that set
            forth in Section 3.4.3 of the same.

      3.    By means of official authorization number 4.612 dated December 21
            2005, issued by SCT, copy of which is attached hereto as Exhibit
            "B", it was authorized in terms of Section 10.6 of the Participation
            Agreement, the assignment by the Strategic Partner in favor of
            Aeroinvest, of the rights and obligations derived from the Purchase
            Option releasing the Strategic Partner

<PAGE>

            from the obligations relating to the Additional Shares, including
            the payment of the price of the same, provided that the other
            obligations on SETA that are derived from the Transaction Documents
            and Participation Agreement, including the cooperation obligation
            referred to in Section 2.3 and the obligations referred to in
            Section 3.4.5 of the Participation Agreement, remain in full force
            and effect.

      4.    Its representative, in its capacity as Deputy Minister for
            Transportation, has sufficient capacity to enter into this Agreement
            according to article 6 of Section IX of the Internal Regulations of
            SCT.

      II.   Nafin represents through its representative that:

      1.    It is a national credit and development-banking institution,
            organized under the Credit Institutions Law and its own Organic Law,
            and has legal capacity and patrimony of its own and that in terms of
            the latter is authorized to enter into this Agreement for the
            purposes herein established.

      2.    On June 14 2005, (i) according to that set forth in Section 3.4.2 of
            the Participation Agreement, the Strategic Partner delivered to
            Nafin the Purchase Notice, expressing in such document its intent to
            exercise the Purchase Option, releasing the Strategic Partner from
            the obligations related to the acquisition of the Additional Shares
            and (ii) and on grounds of the provisions of Section 10.6 of the
            Participation Agreement, the Strategic Partner requested the
            authorization to assign in favor of Aeroinvest all the rights and
            obligations related to the Purchase Option and release the Strategic
            Partner from the obligations regarding the acquisition of the
            Additional Shares, including the payment of the price of the same,
            provided that the other obligations on SETA derived from the
            Transaction Documents and the Participation Agreement, including the
            obligation of cooperation referred to by Section 2.3 and the
            obligations referred to in Section 3.4.5 of the Participation
            Agreement, remain in full force and effect.

      3.    By virtue of the provisions of representation II.2 above, it
            acknowledges the convenience of modifying the Participation
            Agreement, among other things, to eliminate the limitations to
            individual participation of the Controlling Company in terms of that
            provided in Section 3.4.3 of the same.

      4.    That its representative is duly authorized to enter into this
            Purchase and Sale Agreement on its behalf (sic) as it appears in
            public deed number 101,352 granted on July 10 2003, before attorney
            Jose Angel Villalobos Magana, Notary Public number 9 of the Federal
            District and registered with the Public Registry of Commerce of the
            Federal District, under commercial folio number 1275 dated July 16
            2003.

      5.    It has received the necessary instructions to enter into this
            Agreement, in terms of the Trust Agreement number 5111-3 executed on
            June 14 2000 ("The Nafin Trust Agreement").

      III.  The Controlling Company, through its representative represents that:

<PAGE>

      1.    It is a commercial company duly organized and constituted under the
            Mexican Laws, as it appears in public deed number 44,355 of may 28
            1998, granted before attorney Emiliano Zubiria Maqueo, Notary Public
            Number 25 of the Federal District, which first certified copy was
            registered on June 25 1998 in the Public Registry of Commerce of the
            Federal District, under folio number 238749.

      2.    It acknowledges to have entered on June 14 2000 into the
            Participation Agreement.

      3.    It has full knowledge of the Purchase Notice presented by the
            Strategic Partner to Nafin and it acknowledges the need to modify
            the Participation Agreement, among other things, in order to
            eliminate the individual participation limits of the Controlling
            Company in terms of that provided for in Section 3.4.3 of the same.

      4.    By means of the Extraordinary and Ordinary Shareholders Meeting
            Dated December 21st 2005, the shareholders of the Controlling
            Company authorized in terms of Section 10.6 of the Participation
            Agreement, the assignment by the Strategic Partner in favor of
            Aeroinvest, of the rights and obligations derived from the exercise
            of the Purchase Option referred to by Recital 2 (ii) of this
            Agreement, releasing the Strategic Partner from the obligations
            related to the acquisition of Additional Shares, including the
            payment of the price of the same, provided that the other
            obligations on SETA derived from the Transaction Documents and the
            Participation Agreement, including the cooperation obligation
            referred to by Section 2.3 and the obligations referred to in
            Section 3.4.5 of the Participation Agreement, shall remain in full
            force and effect.

      5.    With the execution, compliance and enforcement of this Agreement, it
            does not fail to comply with: (i) any laws or regulations or (ii)
            its by-laws or any contract, agreement or covenant to which it is a
            party, or else, it shall not result in the early termination of its
            binding obligations or in the imposition of restrictions or
            limitations to the investments that Grupo Aeroportuario is bound to
            or intents to make pursuant to the Development Master Program
            referred to by article 38 of the Airports Law or the annual business
            plan of the Controlling Company.

      6.    It has carried out or filed all the notifications and notices and
            has obtained all the authorizations and exemptions, including those
            pertaining to by-laws, that are necessary for the execution,
            compliance and enforcement of this Agreement and the acts
            established in the same.

      7.    That its legal representative has sufficient powers and authorities
            to enter into this Agreement, as it appears in public deed number
            10,485, granted on February 6 2003, before Attorney Jesus Salazar
            Venegas, Notary number 63 of Monterrey, Nuevo Leon, which first
            certified copy was registered on January 27 2004 in the Public
            Registry of Commerce of Monterrey, Nuevo Leon under folio number
            238749.

      IV.   Each and every one of the Concession Companies represent that they
            were incorporated as it was declared in the Participation Agreement
            and that their
<PAGE>

      legal representative has sufficient powers and authority to enter into
      this Agreement.

V.    The Services Company represents through its legal representative, that:

   1.    It is a commercial company duly organized and existing under the laws
         of Mexico, as it appears in public deed number 44,356 granted on May 28
         1998 before Attorney Emiliano Zubiria Maqueo, Notary Public Number 25
         of the Federal District, which first certified copy was registered on
         June 25 1998 with the Public Registry of Commerce of the Federal
         District under commercial folio number 238750.

   2.    It acknowledges to have executed the Participation Agreement on June 14
         2000.

   3.    It has full knowledge of the Purchase Notice presented by the Strategic
         Partner to Nafin and recognizes the need to modify the Participation
         Agreement, among other things, in order to delete the individual
         participation limits of the Controlling Company in terms of that
         established in Section 3.4.3 of the same.

   4.    With the execution, compliance and enforcement of this Agreement, it
         does not violate or fail to comply with: (i) any law, regulation or
         legal provision whatsoever or (ii) its by-laws or any contract,
         agreement or covenant to which it is a party, or else it shall not
         result in the early termination of its binding obligations or in the
         imposition of restrictions or limitations to the investments that Grupo
         Aeroportuario is bound to or wishes to make under the Development
         Master program referred to by Article 38 of the Airports Law or the
         annual business plan of the Controlling Company.

   5.    It has carried out or filed all the notifications and notices and has
         obtained all the authorizations and exemptions, including those
         pertaining to by-laws, which result to be necessary for the execution,
         compliance and enforcement of this Agreement and the acts set forth
         herein.

   6.    Its legal representative has sufficient powers and authority to enter
         into this Agreement pursuant to public deed number 10,486 granted on
         February 6 2003 before Attorney Jesus Salazar Venegas, Notary Public
         number 63 of the Federal District.

VI. The Strategic Partner, through its legal representative, represents that:

   1.    It is a Mexican Company duly organized and existing under the Laws of
         Mexico, by means of public deed number 79,502 date June 9, 2000,
         granted before Attorney Armando Galvez Perez Aragon, Notary Public
         number 103 of the Federal District, which first certified copy was
         registered on October 13 2000 in the Public Registry of Commerce of the
         Federal District under folio number 26,7940.

<PAGE>

   2.    It acknowledges to have entered on June 14 2000 the Participation
         Agreement.

   3.    On June 14 2005, (i) according to that set forth in Section 3.4.2 of
         the Participation Agreement, the Strategic Partner delivered to Nafin
         the Purchase Notice, expressing in such document its intent to exercise
         the Purchase Option, subject to the conditions set forth in such
         Purchase Notice; and (ii) on grounds of the provision of Section 10.6
         of the Participation Agreement, the Strategic Partner requested the
         authorization to assign in favor of Aeroinvest all the rights and
         obligations related to the Purchase Option, releasing the Strategic
         Partner from the obligations regarding the acquisition of the
         Additional Shares, including the payment of the price of the same,
         provided that the other obligations on SETA derived from the
         Transaction Documents and the Participation Agreement, including the
         obligation of cooperation referred to by Section 2.3 and the
         obligations referred to in Section 3.4.5 of the Participation
         Agreement, remain in full force and effect. Such Purchase Notice is
         attached hereto as Exhibit "C".

   4.    It recognizes the need to modify the Participation Agreement, among
         other things, in order to delete the individual participation limits of
         the Controlling Company in terms of that established in Section 3.4.3
         of the same.

   5.    With the execution, compliance and enforcement of this Agreement, it
         does not violate or fail to comply with: (i) any law, regulation or
         legal provision whatsoever or (ii) its by-laws or any contract,
         agreement or covenant to which it is a party, or else it shall not
         result in the early termination of its binding obligations or in the
         imposition of restrictions or limitations to the investments that Grupo
         Aeroportuario is bound to or wishes to make under the Development
         Master Program referred to by Article 38 of the Airports Law or the
         annual business plan of the Controlling Company.

   6.    It has carried out or filed all the notifications and notices and has
         obtained all the authorizations and exemptions, including those
         pertaining to by-laws, which result to be necessary for the execution,
         compliance and enforcement of this Agreement and the acts set forth
         herein.

   7.    Its legal representative has sufficient powers and authority to enter
         into this Agreement pursuant to public deed number 991 dated December
         20 2005, granted before Notary Public number 29 of Monterrey Nuevo
         Leon.

VII. The Partners of the Strategic Partner, through their legal representatives
represent that:

   1.    Each one of them recognizes the need to modify the Participation
         Agreement, among other things, in order to delete the limitations to
         individual participation of the Controlling Company in terms of that
         provided for in Section 3.4.3 of the same.

   2.    On September 14 2005, Vinci y Controladora de Operaciones de
         Infraestructura, S.A. de C.V. ("COINSA") entered into a Purchase and
         Sale

<PAGE>

         Agreement of the shares representing the capital stock of the Strategic
         Partner, held by Vinci, to be subsequently acquired by Aeroinvest. On
         the same date, such shares were acquired by Aeroinvest.

   3.    On November 1st 2005, Aeroinvest notified SCT the transfer of the
         shares representing the capital stock of Aeroinvest owned by Compania
         Empresarial Andrea-J, S.A. de C.V., ("CEA-J") in favor of COINSA and
         one share in favor or Constructoras ICA, S.A. de C.V.

   4.    On 21.12.05, the SCT authorized the transfer of the shares representing
         the capital stock of Aeroinvest held by CEA-J in favor of COINSA and
         one share in favor of Constructoras ICA, S.A. de C.V.

   5.    With the execution, compliance and enforcement of this Agreement, it
         does not violate or fail to comply with: (i) any law, regulation or
         legal provision whatsoever or (ii) its by-laws or any contract,
         agreement or covenant to which it is a party, or else it shall not
         result in the early termination of its binding obligations or in the
         imposition of restrictions or limitations to the investments that Grupo
         Aeroportuario is bound to or wishes to make under the Development
         Master Program referred to by Article 38 of the Airports Law or the
         annual business plan of the Controlling Company.

   6.    It has carried out or filed all the notifications and notices and has
         obtained all the authorizations and exemptions, including those
         pertaining to by-laws, which result to be necessary for the execution,
         compliance and enforcement of this Agreement and the acts set forth
         herein.

   7.    Their legal representatives have sufficient powers and authority to
         enter into this Agreement and that such powers have not been revoked or
         restricted in any manner whatsoever as it appears in:

   (a)   public deed number 69, 898 dated July 25 2003, granted before Attorney
         Jorge Alfredo Dominguez Martinez, Notary Public no. 140 of the Federal
         District, registered with the Public Registry of Commerce of the
         Federal District on September 20 2003 under commercial folio number
         309414, containing the power of attorney of the legal representative of
         Aeroinvest; and

   (b)   Public deed number 112,480 dated December 20 2005, granted before
         attorney Cecilio Gonzalez Marquez, Notary Public no. 151 of the Federal
         District, which contains the power of attorney of the legal
         representative of ADP.

VIII. The Trustee represents, through its legal representative, that:

   1.    In terms of its Organic Law it is authorized to carry out the trust
         operations according to its by-laws and the Law of Credit Institutions.

<PAGE>

   2.    That it attends to the execution of this Agreement, in order to learn
         the scope of its obligations as Trustee under the Participation
         Agreement and to express its agreement to the same.

   3.    That its representative is duly authorized to subscribe this Agreement
         in its name, as it appears in public deed number 32,541, granted on
         January 14 1997, before Attorney Maximinio Garcia Cueto, Notary Public
         no. 14 of the Federal District, same that is duly registered in the
         Public Registry of Property of the Federal District.

IX.   EMICA represents through its legal representative, that:

   1.    That it is a corporation duly organized and validly existing under the
         Laws of Mexico by means of public deed number 97,751 of June 1st 1979,
         granted before Attorney Jesus Castro Figueroa, Notary Public no. 38 of
         the Federal District, registered with the Public Registry of Commerce
         of the Federal District under commercial folio 8723, and that it has
         sufficient powers and authority according to its by-laws to enter into
         this Agreement.

   2.    That its legal representative, Mr. Jose Luis Guerrero Alvarez, has
         sufficient powers and authority to enter into this Agreement, same that
         have not been modified or revoked in any manner whatsoever.

   3.    It is its intent to enter into this Agreement, among other things, to
         become a joint-and-several obligor of Aeroinvest, with respect to all
         the obligations on Aeroinvest derived from the acquisition of the
         Additional Shares, including the obligations set forth under the
         Participation Agreement and the Transaction Documents.

   4.    It knows the terms and scope of the Participation Agreement and the
         Transaction Documents.

   5.    That it acknowledges that, once that the Additional Shares have been
         acquired, Aeroinvest shall also undertake the rights and obligations
         that correspond to the Strategic Partner pursuant to the Transaction
         Documents and the Participation Agreement, expressly including all the
         obligations foreseen in Sections 2.3 and 3.4.5 of the Participation
         Agreement.

   6.    That with the execution, compliance and enforcement of this Agreement,
         it does not violate or infringes: (i) any law, regulation or legal
         provision whatsoever or (ii) its by-laws or any contract, agreement or
         covenant to which it is a party, or else it shall not result in the
         early termination of its binding obligations.

   7.    It has carried out or filed all the notifications and notices and has
         obtained all the authorizations and exemptions, including those
         pertaining to by-laws, which result to be necessary for the execution,
         compliance and enforcement of this Agreement and the acts set forth
         herein.

<PAGE>

Based on the aforementioned representations and warranties, the Parties to this
Agreement agree to modify the Participation Agreement according to the
following:

                                     CLAUSES

FIRST. In terms of Sections 3.4.3 and 10.2.2 of the Participation Agreement, the
parties agree, through the execution of this Agreement, to delete Section 2.5 of
the Participation Agreement titled Participation Limits, as well as any
references to such section whether in the Participation Agreement, the
Transaction Documents or in any other documents.

SECOND. In terms of Sections 3.4.6 of the Participation Agreement and 6.2.6 of
the Shareholders' Agreement and having complied with that provided by Section
10.2.2. of the same Participation Agreement, the parties agree to modify Section
2.7 of the Participation Agreement itself in order to be worded in the following
manner:

      "2.7 Contribution to the Trust. In order to guarantee (i) the negative
covenants foreseen in Section 2.4 above, and (ii) the obligations foreseen in
the Technical Assistance Agreement, the Strategic Partner, the Controlling
Company and the Trustee, agree to enter into the Trust Agreement, in which the
Trustee shall act as such, the Strategic Partner shall act as settlor and first
place beneficiary and the Controlling Company shall act as second place
beneficiary. By virtue of such Trust Agreement, the Strategic Partner shall
transfer to the Trustee the Shares Package so that they [the shares] are kept in
the Trust. In like manner, the obligation shall be established for the Strategic
Partner to transfer to the Trust the Optional Shares that it may eventually
acquire".

THIRD. By virtue of Clause First and Second above, as of the execution of this
Agreement, in regard to the acquisition of shares representing of the capital
stock of the Controlling Company carried out by Aeroinvest, the rights,
obligations, conditions and/or restrictions contemplated by or derived from
Section 2.5 of the Participation Agreement shall not be applicable to the
parties nor shall they have any validity whatsoever.

FOURTH. After having complied with the provisions of Section 10.2.2 of the
Participation Agreement, the parties agree to modify Section 3.4.4 of the
Participation Agreement to be worded in the following manner:

      "3.4.4. In the event that the Strategic Partner has filed a Purchase
      Notice to Nafin, the Strategic Partner or the authorized assignee of the
      rights and obligations derived from such Purchase Notice (in which case
      the Strategic Partner shall not have any obligation in such regard
      whatsoever) shall pay the price in favor of Nafin in dollars, currency of
      the United States of America, or in pesos at the exchange rate of the date
      of the payment as published by Banco de Mexico in the Official Daily of
      the Federation, in immediately available funds, in the form Nafin
      instructs in writing".

FIFTH. The parties acknowledge and ratify, in whatever may refer to each one of
them in the documents or acts to which they are parties, that on the date of
execution of this Agreement, the following acts have taken place or have been
executed by them:

<PAGE>

      1.    An extraordinary and ordinary shareholders' meeting of the
            Controlling Company which resolved on (i) the amendment of the
            by-laws of the Controlling Company to be worded in the form attached
            as Exhibit D of this Agreement; (ii) a dividends policy to be
            followed by the Controlling Company as of the closing date under the
            Agreement for the Purchase and Sale of the Additional Shares (the
            "Closing Date"); (iii) the modification to the composition of the
            Board of Directors of the Controlling Company as of the Closing Date
            under the Purchase and Sale Agreement; and (iv) the conversion of
            the Series "A" shares of the capital stock of the Controlling
            Company into Series "B" shares, among other things.

      2.    An Agreement for the Termination of the Shareholders' Agreement;

      3.    An Agreement to modify the Trust Agreement, in terms of Section
            3.4.6 of the Participation Agreement; and

      4.    An Agreement for the Purchase and Sale of the Additional Shares.

SIXTH. The assignment of the rights and obligations derived from the Purchase
Option or the execution of this Agreement do not release the Strategic Partner
in any manner whatsoever from the compliance of its obligations under the
Transaction Documents and the Participation Agreement and, in an express manner,
those derived from Sections 2.3, 3.4.5 (as long as these refer to the obligation
of cooperating with Nafin in the public offer or offers or other kind of
placement among the public investor of its Shares, even when Nafin keeps the
ownership of 49% or less of the shares representing the capital stock of the
Controlling Company) and 10.3 of the Participation Agreement; provided that the
Strategic Partner does not undertake any obligation whatsoever related to the
Purchase Option or the payment of the Price of the Additional Shares.
Accordingly, Aeroinvest also undertakes the obligations corresponding to the
Strategic Partner according to the Transaction Documents and the Participation
Agreement and which, are its responsibility derived from the acquisition of the
Additional Shares, and in an express manner, those derived from the Sections 2.3
and 3.4.5 of the Participation Agreement (even if Nafin keeps the ownership of
49% or less of the shares representing the capital stock of the Controlling
Company).

Aeroinvest grants and undertakes, as if it were the Strategic Partner, in regard
to itself, the representations and warranties given and undertaken by the
Strategic Partner according to Sections 2.9, 5.2. 5.3. 5.4, 5.5, 5.6 and 5.9 of
the Participation Agreement. The representations and warranties mentioned before
are the determinant reason of Nafin's and SCT's will for the celebration and
compliance of this Agreement and the acts set forth herein.

In the event that a public offer of Shares or other instruments issued on the
Shares is made in Mexico or abroad, or other type of placing that requires the
registration in whole or in part of the Shares or of such instruments in the
National Registry of Securities of the National Banking and Securities
Commission or any other equivalent or substitute registry, the Strategic
Partner, Aeroinvest and Nafin shall carry out all the necessary actions to amend
the by-laws of the Controlling Company to be worded essentially in terms of
Exhibit "D" of this Agreement, and if appropriate, to adapt them
<PAGE>
to any legal or administrative provisions that result to be applicable in order
to be able to carry out any of the aforementioned offers.

The parties agree that, at all times, even when Nafin ceases to be shareholder
of the Controlling Company, the Strategic Partner and Aeroinvest shall require
the written consent of the Federal Government, through SCT, to contract
liabilities or to enter into any type of agreement, by means of which
limitations are imposed to the Controlling Company, the Services Company or any
of the Concession Companies, to carry out any additional investments to those
foreseen in the Development Master Program (as such term is defined in the
Technical Assistance Agreement), business plans or other programs or plans that
result to be applicable or have been approved in regard to the Controlling
Company, the Services Company and/or the Concession Companies.

Furthermore, the parties agree that in the event that Aeroinvest intends to
transfer under any legal title whatsoever, the Additional Shares it acquires
under the Agreement for the Purchase and Sale of such Additional Shares, in
addition to the authorizations and consents that are requested and prior to such
transfer, the acquiring party of any of the Additional Shares shall subscribe
the agreements and documents that are necessary to undertake its terms and the
obligations on Aeroinvest provided in Sections 2.3 and 3.4.5 of the
Participation Agreement, including the amendments thereto.

SEVENTH. Except for the modifications to the Participation Agreement that are
set forth in this Agreement, the Participation Agreement is hereby ratified in
all its terms; therefore, all the provisions of the Participation Agreement that
are not modified by means of this Agreement shall continue having the same
validity and effects with which they were worded in the Participation Agreement.
The parties acknowledge that the modifications set forth in this Agreement do
not constitute a novation to the Participation Agreement.

EIGHTH. Nafin, the Strategic Partner and Aeroinvest upon the acquisition of the
Additional Shares, in their capacity as shareholders of the Controlling Company,
agree and shall carry out all the actions that are necessary to:

      (i)   Instruct the Board of Directors of the latter, to carry out through
            an external consultant of recognized prestige of its choice, an
            analysis for the determination of the best alternative, from the tax
            and operational point of view, to attain an efficient distribution
            of dividends of the Controlling Company, that complies with the
            policy fixed by the Shareholders' Meeting referred to by Section
            (ii) of numeral 1 of Clause fifth of this Agreement and Section 7 of
            the Shareholders Agreement, in order that the same analysis is
            approved, within 120 (one hundred and twenty) calendar days
            following the date of the aforementioned shareholders meeting, by
            the Board of Directors of the Controlling Company, and thereafter to
            be submitted to the consideration of the Shareholders' Meeting of
            the Controlling Company;

      (ii)  To create (i) a reserve fund (the "Reserve Fund") of the Controlling
            Company through one single initial contribution in an amount equal
            to or greater than US$1,000,000.00 (one million U.S. Dollars

<PAGE>

            00/100), in order to have funds to carry out the investments
            contemplated in the Development Master Program referred to by
            Article 38 of the Airports Law or in the annual business plan of the
            Controlling Company and (ii) an Extraordinary Investment Committee
            which shall be comprised of 3 (three) members, from which 2 (two) of
            them shall be appointed by Nafin and 1 (one) by the Strategic
            Partner. The Extraordinary Investment Committee shall be the only
            organ authorized to determine the destination and application of the
            resources of the reserve Fund. Such Committee may be called by any
            of its members at least 3 (three) business days in advance. The
            Committee may also adopt the resolutions outside a meeting, provided
            they are ratified by all its members. In order for a meeting to be
            duly convened, at least 2 (two) of its members may be present and,
            subject to that provided for in the following paragraph, its
            decisions shall be adopted by a simple majority, provided that the
            Chairman shall have a tie-breaking vote.

In the event that the totality or part of the resources maintained in the
Reserve Fund had been disposed of, the favorable vote of the totality of the
members of the Extraordinary Investments Committee shall be required in order to
make new contributions to such Reserve Fund.

Notwithstanding the above, the resources maintained by the Controlling Company
in the Reserve Fund shall only be disposed of by the Extraordinary Investments
Committee once that each and every remedy set forth in the Development Master
Program and the annual business plan of the Controlling Company have been
exhausted or in the event that, there are funds according to such plans, these
are not applied to the corresponding extraordinary investments.

The Reserve Fund Shall only be kept by the Controlling Company, as long as Nafin
participates in the Controlling Company, whether directly or indirectly, at
least in 49% (forty nine percent) of the capital stock. Consequently, once that
Nafin participates in the Controlling Company with a percentage lower than 49%
(forty nine percent) of the capital stock of the same, such Reserve Fund shall
be absorbed by the Controlling Company and the Extraordinary Investments
Committee shall cease in its duties.

(iii) As long as the shares of the Controlling Company are not listed in any
stock exchange and provided that Nafin participates in the Controlling Company,
whether directly or indirectly, with at least 49% (forty nine percent) of the
capital stock, the favorable vote of at least 60% (sixty percent) of the capital
stock of the Controlling Company shall be required for the contracting or
undertaking, whether directly or indirectly, of any debt, liabilities or
commitments of the Controlling Company to or resulting in, or which purpose may
be to carry out any type of allocation, whether in cash or kind, to the
shareholders of the Controlling Company, including without limitation, any
decreases to the capital stock through the reimbursement, redemption of shares,
payment of liquidation quotas or payment of dividends.

NINTH. EMICA agrees to constitute itself as joint-and-several obligor as to each
and every obligations of Aeroinvest derived from the acquisition of Additional
Shares

<PAGE>

by virtue of this Agreement, including without limitation, the obligations set
forth under the Participation Agreement and the Transaction Documents.

Further, EMICA hereby undertakes the obligation of carrying out each and every
action and adopting any agreement that result convenient or necessary for the
faithful compliance by Aeroinvest of each and every one of its obligations
derived from the loan agreement (the "Loan Agreement") dated December 14 2005,
in the amount of US$125,000,000.00 (one hundred and twenty five million U.S.
Dollars) entered, among others, by Aeroinvest as borrower and WestLB AG, New
York Branch as lender and administrative Agent, including the direct compliance
of the same, so that Aeroinvest keeps the ownership of the Additional Shares and
the corporate rights corresponding to the same. For such purposes, in the same
date of the Loan Agreement, EMICA becomes joint-and-several obligor with respect
to the obligations of Aeroinvest under the Loan Agreement, by means of the
guarantee subscribed between EMICA and WestLB AG New York Branch (Guarantee)
dated December 14 2005, same obligation that shall remain in full force during
the effectiveness of the Loan Agreement or any other loan substituting the Loan
Agreement.

The parties agree that (A) while Aeroinvest is the owner, whether directly or
indirectly of the Additional Shares, Aeroinvest shall exercise the voting right
of the same, provided that it may agree to vote the same in the same manner than
those held by the Strategic Shareholder; (B) in the event that the Additional
Shares are transferred to a trust, Aeroinvest as fiduciary or beneficiary of the
Additional Shares under the same or under any similar instrument, as long as the
relevant trustee has not received a notice of default in terms of the
corresponding trust agreement, Aeroinvest shall instruct the trustee of the
relevant trust on the form of exercising the voting right of the Additional
Shares, in the understanding that it may instruct the trust to vote such
Additional Shares in the same manner than the Shares held by the Strategic
Partner; and (C) in the event that the Additional Shares are kept in a trust
according to paragraph B above, and a notice of default has been received in
terms of the relevant trust agreement, the corresponding beneficiary shall
instruct the trustee to vote the Additional Shares, in the understanding that
such shares should always be voted in the same manner as the Shares held by the
Strategic Partner, provided however that the compliance of the obligations
guaranteed under the Credit Agreement is not affected or the capacity of
Aeroinvest to comply with its obligations under the Loan Agreement is not
limited in any manner whatsoever.

TENTH. This Agreement shall be ruled and enforced according to the federal laws
of the United Mexican States and the parties, expressly and irrevocably, submit
themselves to the jurisdiction of the competent courts of Mexico City, Federal
District, United Mexican States, expressly waiving to any other jurisdiction
that may correspond to them by reason of their present or future domiciles or by
any other concepts.

According to the above, and being the parties aware of the validity and legal
scope of this Agreement, they sign it on the 21st day of the month of December
2005.

              [the rest of the page is intentionally left in blank]

<PAGE>

                                [Signature Sheet]
Agreement for the Modification of the Participation Agreement Dated December
21st 2005

                Nacional Financiera, Sociedad Nacional de Credito
                                 Trust Division

                              (illegible signature)
                          --------------------------------
                      By: Ricardo Rangel Fernandez McGregor
                         Position: Legal Representative

<PAGE>

                                [Signature Sheet]
Agreement for the Modification of the Participation Agreement Dated December
21st 2005

        The Federal Government, through the Department of Communications
                                 And Transports

                              (illegible signature)
                          --------------------------------
                          By: Aaron Dychter Poltolarek
                      Position: Transports Deputy Secretary

<PAGE>

                                [Signature Sheet]
Agreement for the Modification of the Participation Agreement Dated December
21st 2005

                   Banco Nacional de Comercio Exterior, S.N.C.

                              (illegible signature)
                          --------------------------------
                            By: Carlos Flores Salinas
                         Position: Legal Representative

<PAGE>

                                [Signature Sheet]
Agreement for the Modification of the Participation Agreement Dated December
21st 2005

                            Aeroinvest, S.A. de C.V.

                              (illegible signature)
                          -----------------------------
                           By: Alonso Quintana Kawage
                         Position: Legal Representative

                           Empresas ICA, S.A. de C.V.

                              (illegible Signature)

                          -----------------------------
                         By: Jose Luis Guerrero Alvarez
                         Position: Legal Representative

<PAGE>

                                [Signature Sheet]
Agreement for the Modification of the Participation Agreement Dated December
21st 2005

                               Aeroports de Paris

                              (illegible signature)
                          ----------------------------
                               By: Nicolas Claude
                         Position: Legal Representative

<PAGE>

                                [Signature Sheet]
Agreement for the Modification of the Participation Agreement Dated December
21st 2005

               Servicios de Tecnologia Aeroportuaria, S.A. de C.V.

                             (illegible signature)
                          ----------------------------
                              By: Luis Zarate Rocha
                         Position: Legal Representative

<PAGE>

                                [Signature Sheet]
Agreement for the Modification of the Participation Agreement Dated December
21st 2005

Aeropuerto de Ciudad Juarez, S.A.
De C.V.
  (illegible signature)
-------------------------
By: Ruben Lopez Barrera
Position: Legal Representative

Aeropuerto de Culiacan, S.A. de
C.V.
  (illegible signature)
-------------------------
By: Ruben Lopez Barrera
Position: Legal Representative

Aeropuerto de Acapulco, S.A. de
C.V.
  (illegible signature)
-------------------------
By: Ruben Lopez Barrera
Position: Legal Representative

Aeropuerto de Mazatlan, S.A.
De C.V.
  (illegible signature)
-------------------------
By: Ruben Lopez Barrera
Position: Legal Representative

Aeropuerto de Reynosa, S.A. de
C.V.
  (illegible signature)
-------------------------
By: Ruben Lopez Barrera
Position: Legal Representative

Aeropuerto de Chihuahua, S.A.
de C.V.
  (illegible signature)
-------------------------
By: Ruben Lopez Barrera
Position: Legal Representative

Aeropuerto de Chihuahua, S:A. de C.V.
  (illegible signature)
-------------------------
By: Ruben Lopez Barrera
Position: Legal Representative

Aeropuerto de Durango, S.A.
De C.V.
  (illegible signature)
-------------------------
By: Ruben Lopez Barrera
Position: Legal Representative

<PAGE>

Aeropuerto de Monterrey, S.A. de
C.V.
  (illegible signature)
-------------------------
By: Ruben Lopez Barrera
Position: Legal Representative

Aeropuerto de Tampico, S.A. de
C.V.
  (illegible signature)
-------------------------
By: Ruben Lopez Barrera
Position: Legal Representative

Aeropuerto de Torreon, S.A. de
C.V.
  (illegible signature)
-------------------------
By: Ruben Lopez Barrera
Position: Legal Representative

Aeropuerto de Zacatecas, S.A. de
C.V.
  (illegible signature)
-------------------------
By: Ruben Lopez Barrera
Position: Legal Representative

Aeropuerto de San Luis Potosi, S.A. de
C.V.
  (illegible signature)
-------------------------
By: Ruben Lopez Barrera
Position: Legal Representative

Aeropuerto de Zihuatanejo, S.A. de
C.V.
  (illegible signature)
-------------------------
By: Ruben Lopez Barrera
Position: Legal Representative

<PAGE>

                                [Signature Sheet]
Agreement for the Modification of the Participation Agreement Dated December
21st 2005

             Servicios Aeroportuarios del Centro Norte, S.A. de C.V.

                              (illegible signature)
                            --------------------------
                             By: Ruben Lopez Barrera
                         Position: Legal Representative

<PAGE>

                                [Signature Sheet]
Agreement for the Modification of the Participation Agreement Dated December
21st 2005

               Grupo Aeroportuario del Centro Norte, S.A. de C.V.

                              (illegible signature)
                            --------------------------
                             By: Ruben Lopez Barrera
                         Position: Legal Representative

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