<PAGE>   1
                                                                    EXHIBIT 4.11


--------------------------------------------------------------------------------




                             NOTE PURCHASE AGREEMENT

                          Dated as of December 14, 2000

                                     between

                             UNITED AIR LINES, INC.,

                                       and

                       STATE STREET BANK AND TRUST COMPANY
                      OF CONNECTICUT, NATIONAL ASSOCIATION,
                    as Pass Through Trustee under each of the
              United Airlines 2000-2 Pass Through Trust Agreements,
                    Subordination Agent and Indenture Trustee




--------------------------------------------------------------------------------


<PAGE>   2


                                TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                            Page
                                                                            ----

<S>                                                                           <C>
    SECTION 1.   Purchase of Notes.............................................2
    SECTION 1.A. Certain Definitions...........................................2
    SECTION 2.   [Reserved.....................................................3
    SECTION 3.   Conditions Precedent..........................................3
    SECTION 4.   Representations, Warranties and Covenants of United...........8
    SECTION 5.   Representations, Warranties and Covenants of Other Parties...10
    SECTION 6.   Notices......................................................15
    SECTION 7.   Expenses.....................................................15
    SECTION 8.   Miscellaneous................................................15

SCHEDULES

Schedule I   Names, Addresses and Wire Instructions

Schedule II  Notes, Purchasers and Purchase Prices
</TABLE>



<PAGE>   3


                             NOTE PURCHASE AGREEMENT


         This NOTE PURCHASE AGREEMENT, dated as of December 14, 2000 (this
"Agreement"), between UNITED AIR LINES, INC., a Delaware corporation ("United"),
and STATE STREET BANK AND TRUST COMPANY OF CONNECTICUT, NATIONAL ASSOCIATION, a
national banking association (the "Bank"), not in its individual capacity,
except as otherwise expressly provided herein, but solely as trustee (in such
capacity, the "Pass Through Trustee") under each of the four separate Pass
Through Trust Agreements (as defined below), subordination agent (in such
capacity, the "Subordination Agent"), and indenture trustee (in such capacity,
the "Indenture Trustee") under the Indentures (as defined below).

         WHEREAS, United is the owner of twelve Airbus A319-131 aircraft, six
Airbus A320-232 aircraft, seven Boeing 757-222 aircraft, three Boeing 747-422
aircraft and nine Boeing 777-200ER aircraft (collectively, the "Aircraft") for
which it desires to obtain financing;

         WHEREAS, pursuant to each Trust Indenture and Mortgage, dated as of the
date hereof (each, an "Indenture"), between United and the Indenture Trustee
thereunder, United proposes to issue up to five series of equipment notes (the
"Notes"), of which United proposes to issue four series on the Closing Date and
may, in the future, issue such fifth series, all of which, regardless of when
issued, are to be secured by the mortgage and security interest in the related
Aircraft granted pursuant to such Indenture by United in favor of the related
Indenture Trustee and to be subject to the subordination provisions contained
therein;

         WHEREAS, Series A-1 Notes, Series A-2 Notes, Series B Notes and Series
C Notes with respect to each Aircraft (each, a "Series") will be issued on the
Closing Date (as defined in Section 1 below) to the Subordination Agent acting
on behalf of the Pass Through Trustee for the applicable Pass Through Trust as
evidence of United's indebtedness to the Pass Through Trustee;

         WHEREAS, pursuant to each of the Pass Through Trust Supplements (the
"Trust Supplements"; and together with the Basic Pass Through Trust Agreement,
the "Pass Through Trust Agreements"), on the Closing Date (as defined in Section
1 below), a separate grantor trust (each, a "Pass Through Trust") will be
created to facilitate certain of the transactions contemplated hereby,
including, without limitation, the issuance and sale of enhanced pass through
certificates pursuant thereto (collectively, the "Pass Through Certificates") to
provide the financing of the Aircraft;

         WHEREAS, part of the proceeds from the issuance and sale of the Pass
Through Certificates will be applied by the Subordination Agent, acting on
behalf of the Pass Through Trustee, to purchase from United on behalf of each
Pass Through Trust, the Notes bearing the same interest rate as the Pass Through
Certificates issued by the related Pass Through Trust; and

         WHEREAS, concurrently with the execution and delivery of this
Agreement, (i) Westdeutsche Landesbank Girozentrale, a German banking
institution organized under the


<PAGE>   4

                                              [(2000-2) Note Purchase Agreement]

laws of the State of North Rhine-Westphalia, Germany, acting through its New
York branch (the "Liquidity Provider") entered into four revolving credit
agreements (each, a "Liquidity Facility") for the benefit of the United Airlines
2000-2A-1 Pass Through Trust, the United Airlines 2000-2A-2 Pass Through Trust,
the United Airlines 2000-2B Pass Through Trust and the United Airlines 2000-2C
Pass Through Trust, with the Subordination Agent, as agent and trustee for the
Pass Through Trustee on behalf of each such Pass Through Trust; and (ii) the
Pass Through Trustee, the Liquidity Provider and the Subordination Agent entered
into the Intercreditor Agreement, dated as of the date hereof (the
"Intercreditor Agreement");

         NOW, THEREFORE, in consideration of the foregoing and the mutual
agreements contained herein, the parties hereto agree as follows:

         SECTION 1. Purchase of Notes. (a) Subject to the satisfaction or waiver
of the conditions set forth herein, on December 14, 2000, or on such other date
agreed to by the parties hereto (the "Closing Date"):

                           (i) the Pass Through Trustee for each Pass Through
         Trust shall pay to United the purchase price set forth on Schedule II
         for each Note being issued and sold by United to such Pass Through
         Trust; and

                           (ii) United shall issue, pursuant to Article 2 of
         each Indenture, to the Subordination Agent, on behalf of the Pass
         Through Trustee for each of the Pass Through Trusts, a Note having the
         Series, maturity date and principal amount and bearing the interest
         rate set forth on Schedule II opposite the name of such Pass Through
         Trust.

                  (b) All payments pursuant to Section 1(a)(i) shall be made in
immediately available funds to such accounts and at such banks as United shall
designate on Schedule I or as it may otherwise designate in writing not less
than one Business Day prior to the Closing Date.

         SECTION 1.A. Certain Definitions. (a) As used in this Agreement and
unless otherwise expressly provided, the following capitalized terms shall have
the following respective meanings:

         "FAA" means the Federal Aviation Administration.

         "Federal Aviation Act" means Title 49 of the United States Code
(Transportation), as amended.

         "Fundamental Documents" shall mean, collectively (i) any document that
is a "Fundamental Document" under and as defined in any Indenture and (ii) any
amendment to any of the foregoing executed in connection with the transactions
contemplated hereby.


                                       2
<PAGE>   5

                                              [(2000-2) Note Purchase Agreement]

         "Operative Documents" shall mean any document that is an Operative
Document under an Indenture.

                  (b) Unless otherwise specifically defined herein, capitalized
terms used in this Agreement shall have the respective meanings specified in the
Intercreditor Agreement.

         SECTION 2. [Reserved.]

         SECTION 3. Conditions Precedent. (a) Conditions Precedent to the
Obligations of the Pass Through Trustee. The obligation of the Pass Through
Trustee to make the payments described in Section 1(a)(i) and to enter into the
Fundamental Documents to which it is a party are subject to the fulfillment, on
or prior to the Closing Date, of the following conditions precedent:

                           (i) No change shall have occurred after the date of
         the execution and delivery of this Agreement in applicable law or
         regulations thereunder or interpretations thereof by appropriate
         regulatory or judicial authorities which, in the opinion of each Pass
         Through Trustee, would make it a violation of law or regulations for
         the Pass Through Trustee to make the payments described in Section
         1(a), to execute, deliver and perform the Fundamental Documents, to
         acquire the Notes or to realize the security afforded by the
         Indentures.

                           (ii) United shall have tendered the Notes to the
         applicable Indenture Trustee for authentication and shall have tendered
         the Notes to the Subordination Agent on behalf of the Pass Through
         Trustee in accordance with Section 1.

                           (iii) The Pass Through Trustee shall have received
         duly authorized and validly executed counterparts or conformed copies
         of the following documents in form and substance satisfactory to the
         Pass Through Trustee and all such documents shall be in full force and
         effect:

                                    (A) this Agreement;

                                    (B) the Basic Pass Through Trust Agreement
                  and each Trust Supplement;

                                    (C) the Intercreditor Agreement;

                                    (D) the Liquidity Facility for each of the
                  Class A-1 Trust, the Class A-2 Trust, the Class B Trust and
                  the Class C Trust;


                                       3
<PAGE>   6

                                              [(2000-2) Note Purchase Agreement]

                                    (E) the Indentures; and

                                    (F) the Underwriting Agreement.

                           (iv) Uniform Commercial Code financing statements
         covering all the security interests created by or pursuant to the
         Granting Clause of each Indenture shall have been executed and
         delivered by United and the relevant Indenture Trustee, and such
         financing statements shall have been duly filed or arrangements
         satisfactory to the Pass Through Trustee shall have been made for
         filing within 10 days after the Closing Date, with the Secretary of
         State of the State of Illinois and any other places deemed necessary or
         advisable.

                           (v) The Pass Through Trustee shall have received the
         following, in each case in form and substance satisfactory to it:

                                    (A) a certified copy of the Restated
                  Certificate of Incorporation and By-Laws of United and a copy
                  of resolutions of the board of directors of United or the
                  executive committee thereof, certified by the Secretary or an
                  Assistant Secretary of United, duly authorizing the execution,
                  delivery and performance by United of this Agreement and each
                  other Fundamental Document required to be executed and
                  delivered by United in accordance with the provisions hereof
                  and thereof;

                                    (B) a copy of the organizational documents,
                  by-laws and general authorizing resolutions of the boards of
                  directors (or executive committees) or other satisfactory
                  evidence of authorization of each Indenture Trustee and the
                  Subordination Agent, certified as of the Closing Date by the
                  Secretary or an Assistant Secretary of such parties,
                  respectively, which authorize the execution, delivery and
                  performance by each Indenture Trustee and the Subordination
                  Agent, respectively, of all the Fundamental Documents to which
                  it is a party, together with such other documents and evidence
                  with respect to each Indenture Trustee and the Subordination
                  Agent as the Pass Through Trustee may reasonably request in
                  order to establish the consummation of the transactions
                  contemplated by this Agreement, the taking of all corporate
                  proceedings in connection therewith and compliance with the
                  conditions herein set forth; and

                                    (C) a certificate signed by the Secretary or
                  an Assistant Secretary of each of United, each Indenture
                  Trustee and the Subordination Agent as to the Person or
                  Persons authorized to execute and deliver this Agreement and
                  any other Fundamental Document to be executed on behalf of
                  such party in


                                       4
<PAGE>   7

                                              [(2000-2) Note Purchase Agreement]

                  connection with the transactions contemplated hereby and as to
                  the signature of such Person or Persons.

                           (vi) On the Closing Date, (A) the representations and
         warranties of United contained in Section 4 and the representations and
         warranties of each Indenture Trustee and the Subordination Agent
         contained in Section 5 shall be true and correct in all material
         respects as though made on and as of such date, except to the extent
         that such representations and warranties relate solely to an earlier
         date (in which case such representations and warranties shall have been
         true and correct in all material respects on and as of such earlier
         date), and (B) no event shall have occurred and be continuing, or would
         result from the transactions contemplated hereby, which constitutes (or
         would, with the passage of time or the giving of notice or both,
         constitute) an Indenture Default under any Indenture.

                           (vii) The Pass Through Trustee shall have received an
         opinion addressed to the Pass Through Trustee from (A) the General
         Counsel or Assistant General Counsel for United and (B) Vedder, Price,
         Kaufman & Kammholz, special counsel for United, in each case with
         respect to such matters and in form and substance reasonably
         satisfactory to the Pass Through Trustee.

                           (viii) The Pass Through Trustee shall have received
         an opinion addressed to the Pass Through Trustee and United from (A) in
         house German counsel of the Liquidity Provider, and (B) Shearman &
         Sterling, special counsel for the Liquidity Provider, in each case in
         form and substance reasonably satisfactory to the Pass Through Trustee.

                           (ix) The Pass Through Trustee shall have received an
         opinion addressed to the Pass Through Trustee and United from Lytle
         Soule & Curlee, special counsel in Oklahoma City, Oklahoma, in form and
         substance reasonably satisfactory to the Pass Through Trustee.

                           (x) The Pass Through Trustee shall have received an
         opinion addressed to the Pass Through Trustee and United from Bingham
         Dana LLP, special counsel for the Indenture Trustees and the Pass
         Through Trustee, in form and substance reasonably satisfactory to the
         Pass Through Trustee.

                           (xi) The Pass Through Trustee shall have received an
         opinion addressed to the Pass Through Trustee and United from Vedder,
         Price, Kaufman & Kammholz, special New York counsel for United, in form
         and substance reasonably satisfactory to the Pass Through Trustee.


                                       5
<PAGE>   8

                                              [(2000-2) Note Purchase Agreement]

                           (xii) The Pass Through Trustee shall have received an
         independent insurance broker's report, and certificates of insurance,
         in form and substance reasonably satisfactory to it, as to the due
         compliance with the terms of Section 4.03 of each Indenture with
         respect to the Aircraft.

                           (xiii) The Pass Through Trustee shall have received a
         report from each of the Appraisers as to the base value of the
         Aircraft, in form and substance satisfactory to the Pass Through
         Trustee and United.

                           (xiv) The conditions precedent to the transactions
         specified in the Underwriting Agreement shall have been satisfied (or
         waived) in accordance with the terms thereof.

                           (xv) With respect to each Aircraft, the applicable
         Indenture shall have been duly filed with the FAA.

                           (xvi) The conditions precedent under each
         Participation Agreement relating to an Aircraft shall have been
         satisfied (or waived) in accordance with the terms thereof.

Promptly upon the recording of the Indentures pursuant to the Federal Aviation
Act, United shall cause Lytle Soule & Curlee, special counsel in Oklahoma City,
Oklahoma, to deliver to the Pass Through Trustee an opinion as to the due
recording by the FAA of the Indentures and the lack of any intervening filings
with respect to the Aircraft.

                  (b) Conditions Precedent to the Obligations of United. The
obligations of United to participate in the transactions contemplated hereby and
to enter into the Fundamental Documents to which United is a party are all
subject to the fulfillment to the satisfaction of or waiver by United, on or
prior to the Closing Date, of the following conditions precedent:

                           (i) Those documents described in Section 3(a)(iii)
         shall have been duly authorized, executed and delivered by the
         respective party or parties thereto (other than United) in the manner
         specified in Section 3(a)(iii), shall each be satisfactory in form and
         substance to United, shall be in full force and effect on the Closing
         Date, and an executed counterpart of each thereof shall have been
         delivered to United or counsel for United.

                           (ii) United shall have received a copy of the
         organizational documents, by-laws and general authorizing resolutions
         of the boards of directors (or executive committees) or other
         satisfactory evidence of authorization of each Indenture Trustee, the
         Pass Through Trustee and the Subordination Agent, certified as of the
         Closing Date by


                                       6
<PAGE>   9

                                              [(2000-2) Note Purchase Agreement]

         the Secretary or an Assistant Secretary of each such party,
         respectively, that authorize the execution, delivery and performance by
         each Indenture Trustee, the Pass Through Trustee and the Subordination
         Agent, respectively, of all the Fundamental Documents to which each
         such party is a party, together with such other documents and evidence
         with respect to each Indenture Trustee, the Pass Through Trustee and
         the Subordination Agent as United or its counsel may reasonably request
         in order to establish the consummation of the transactions contemplated
         by this Agreement, the taking of all corporate proceedings in
         connection therewith and compliance with the conditions set forth
         herein.

                           (iii) A certificate signed by the Secretary or an
         Assistant Secretary of each Indenture Trustee, the Pass Through Trustee
         and the Subordination Agent as to the Person or Persons authorized to
         execute and deliver this Agreement and any other Fundamental Document
         to be executed on behalf of such party in connection with the
         transactions contemplated hereby and as to the signature of such Person
         or Persons.

                           (iv) The representations and warranties of each
         Indenture Trustee, the Pass Through Trustee and the Subordination Agent
         contained in Section 5 shall be true and correct in all material
         respects as of the Closing Date as though made on and as of such date,
         except to the extent that such representations and warranties relate
         solely to an earlier date (in which event such representations and
         warranties shall have been true and correct in all material respects on
         and as of such earlier date).

                           (v) United shall have received the opinions set forth
         in Sections 3(a)(vii)-3(a)(xi) (except receipt by United of the
         opinions set forth in Sections 3(a)(vii) and 3(a)(xi) shall not be a
         condition precedent to its obligations hereunder), in each case
         addressed to United and dated the Closing Date and otherwise in form
         and substance satisfactory to United.

                           (vi) United shall have received a copy of the reports
         required to be delivered pursuant to Section 3(a)(xiii).

                           (vii) The conditions precedent to the transactions
         specified in the Underwriting Agreement shall have been satisfied (or
         waived) in accordance with the terms thereof.

                           (viii) No change shall have occurred after the date
         of the execution and delivery of this Agreement in applicable law or
         regulations thereunder or interpretations thereof by appropriate
         regulatory authorities which, in the opinion of United, would make it a
         violation of law or regulations for United to enter into any
         transaction contemplated by the Fundamental Documents.


                                       7
<PAGE>   10

                                              [(2000-2) Note Purchase Agreement]

         SECTION 4. Representations, Warranties and Covenants of United. United
represents, warrants and covenants to the Pass Through Trustee and each
Indenture Trustee that:

                  (a) United is a corporation duly organized and validly
existing in good standing pursuant to the laws of the State of Delaware; is a
Citizen of the United States and a Certificated Air Carrier; has its chief
executive office (as such term is defined in Article 9 of the Uniform Commercial
Code) at 1200 East Algonquin Road, Elk Grove Township, Illinois 60007; is duly
qualified to do business as a foreign corporation in each jurisdiction in which
it has intrastate routes or has its principal office or a major overhaul
facility, except where the failure to be so qualified would not have a material
adverse effect on the ability of United to perform its obligations under the
United Documents (as defined below); holds all material licenses, certificates,
permits and franchises from the appropriate agencies of the United States of
America and/or all other governmental authorities having jurisdiction, necessary
to authorize United to engage in and to carry on scheduled passenger service, in
each case as presently conducted, and has the corporate power and authority to
enter into and perform its obligations under this Agreement, the Notes issued
under the Indentures and each other Fundamental Document to which it is a party
(collectively, the "United Documents").

                  (b) The execution, delivery and performance by United of the
United Documents have been duly authorized by all necessary corporate action on
the part of United, do not require any stockholder approval, or approval or
consent of any trustee or holders of any indebtedness or obligations of United
except such as have been duly obtained, and none of the execution, delivery and
performance by United of such United Documents contravenes any law, judgment,
governmental rule, regulation or order binding on United or the certificate of
incorporation or by-laws of United or contravenes the provisions of, or
constitutes a default under, or results in the creation of any Lien (other than
Permitted Liens (as defined in the Indentures)) upon the property of United
under: (x) its certificate of incorporation or bylaws; or (y) any indenture,
mortgage, chattel mortgage, deed of trust, conditional sales contract, bank loan
or credit agreement or other agreement or instrument to which United is a party
or by which it or its properties may be bound or affected, except for any such
contravention, default or Lien pertaining to an agreement of the type listed in
clause (y) of this Section that, individually or in the aggregate, would be
reasonably unlikely to have a material adverse effect on the ability of United
to perform its obligations under the United Documents.

                  (c) Neither the execution and delivery by United of the United
Documents nor the performance by United of its obligations thereunder require
the consent or approval of, the giving of notice to, the registration with, or
the taking of any other action in respect of any federal, state, local or
foreign government authority or agency, except for (A) the qualification of the
Pass Through Trust Agreements under the Trust Indenture Act of 1939, as amended,
pursuant to an order of the Securities and Exchange Commission, (B) the
registrations and filings referred to in Section 3(a)(iv), (C) authorizations,
consents, approvals, actions, notices and filings


                                       8
<PAGE>   11

                                              [(2000-2) Note Purchase Agreement]

required to be obtained, taken, given or made which have been duly obtained and
are in full force and effect or the failure of which to obtain, take, give or
make would not have a material adverse effect on the financial condition,
properties or results of operations of United or on the ability of United to
perform its obligations under the United Documents, (D) any normal periodic and
other reporting requirements under the applicable rules and regulations of the
FAA to the extent required to be given or obtained only after the Closing Date,
and (E) the recordings with the FAA described in the opinion referred to in
Section 3(a)(ix).

                  (d) Each of the United Documents has been duly executed and
delivered by United and constitutes legal, valid and binding obligations of
United enforceable against United in accordance with the terms thereof, except
as the same may be limited by (a) applicable bankruptcy, insolvency, fraudulent
conveyance, reorganization, moratorium or similar laws affecting the enforcement
of creditors' rights generally, (b) by general principles of equity, whether
considered in a proceeding at law or in equity, (c) in the case of indemnity
provisions contained in such documents, public policy considerations, and (d) in
the case of the Indentures, applicable laws which may affect the remedies
provided in the Indentures, which laws, however, do not make the remedies
provided in the Indentures inadequate for practical realization of the benefits
intended to be afforded thereby.

                  (e) There has not occurred any event which constitutes an
Indenture Default under any Indenture which is presently continuing and there
has not occurred any event which constitutes or would, with the passage of time
or the giving of notice, or both, constitute an Event of Loss (as defined in the
applicable Indenture) under any Indenture.

                  (f) Neither United nor anyone acting on behalf of United has
offered any interest in any Pass Through Certificate or any Note in a manner
which would violate the Securities Act of 1933, as amended, the regulations
thereunder, administrative and judicial interpretation thereof or the securities
laws, rules or regulations of any state.

                  (g) Neither United nor any subsidiary of United is an
"investment company" or a company "controlled by an investment company" within
the meaning of the Investment Company Act of 1940, as amended.

                  (h) Except for the proceedings described in the discussion of
Legal Proceedings in United's Annual Report on Form 10-K for the year ended
December 31, 1999 and subsequently filed Form 10-Qs filed prior to the Closing
Date, there are no pending or, to the knowledge of United, threatened actions or
proceedings before any court or administrative agency which individually (or in
the aggregate in the case of any group of related lawsuits) would have a
material adverse effect on the ability of United to perform its obligations
under the United Documents or that seek to set aside, restrain, enjoin or
prevent the consummation of this


                                       9
<PAGE>   12

                                              [(2000-2) Note Purchase Agreement]

Agreement, the other Fundamental Documents or the transactions contemplated
hereby or thereby.

                  (i) None of the proceeds from the issuance of the Notes will
be used directly or indirectly by United to purchase or carry any "margin stock"
as such term is defined in Regulation T or U of the Board of Governors of the
Federal Reserve System.

                  (j) United agrees to pay to the Subordination Agent any
amounts required to be paid by the Subordination Agent pursuant to Sections
2.03, 3.01, 3.02, 3.03, 3.09, 7.05 and 7.07 of any Liquidity Facility.

                  (k) United agrees to give each Indenture Trustee and the Pass
Through Trustee at least 30 days' prior written notice of any relocation of its
chief executive office from its present location.

                  (l) If United were to become a debtor under the Bankruptcy
Code, each Indenture Trustee, as secured party under the related Indenture,
would be entitled to the benefits of Section 1110 of the Bankruptcy Code with
respect to the relevant Aircraft.

                  (m) Each Aircraft has been duly certified by the FAA as to
type and airworthiness and such certification remains in full force and effect.

                  (n) With respect to the Aircraft, the applicable Indenture has
been duly filed for recording with the FAA pursuant to the Federal Aviation Act.

         SECTION 5. Representations, Warranties and Covenants of Other Parties.
Each of the parties below represents, warrants and covenants to each of the
other parties to this Agreement as follows:

                  (a) Each Indenture Trustee represents, warrants and covenants
that:

                           (i) such Indenture Trustee is a national banking
         association duly organized, validly existing and in good standing under
         the laws of the United States of America, is a "citizen of the United
         States" as defined in 49 U.S.C. Section 40102(a)(15) (without making
         use of a voting trust agreement, voting powers agreement or similar
         arrangements) and will resign as Indenture Trustee promptly after it
         obtains actual knowledge that it has ceased to be such a citizen, and
         has, or had on the respective dates of execution thereof, the full
         corporate power, authority and legal right under the laws of the State
         of Connecticut and the United States of America pertaining to its
         banking, trust and fiduciary powers to execute and deliver this
         Agreement and each other Fundamental


                                       10
<PAGE>   13

                                              [(2000-2) Note Purchase Agreement]

         Document to which it is a party, to authenticate the Notes and to carry
         out its obligations under this Agreement and each other Fundamental
         Document to which it is a party;

                           (ii) the execution and delivery by such Indenture
         Trustee of this Agreement and each other Fundamental Document to which
         it is a party, the authentication of the Notes and the performance by
         such Indenture Trustee of its obligations under this Agreement and each
         other Fundamental Document to which it is a party have been duly
         authorized by such Indenture Trustee and will not violate its charter
         or by-laws, the provisions of any indenture, mortgage, contract or
         other agreement to which it is a party or by which it is bound or any
         federal or Connecticut law or regulation relating to the banking, trust
         or fiduciary powers of such Indenture Trustee;

                           (iii) this Agreement and each other Fundamental
         Document to which such Indenture Trustee is a party have been duly
         authorized, executed and delivered by such Indenture Trustee; this
         Agreement constitutes, and each Fundamental Document to which such
         Indenture Trustee is a party, when it has been executed and delivered
         by such Indenture Trustee, will constitute, the legal, valid and
         binding obligations of such Indenture Trustee enforceable against it in
         accordance with their respective terms, except as the same may be
         limited by applicable bankruptcy, insolvency, reorganization,
         moratorium or similar laws affecting the rights of creditors generally
         and by general principles of equity, whether considered in a proceeding
         at law or in equity;

                           (iv) no consent, approval, order or authorization of,
         giving of notice to, or registration or filing with, or taking of any
         other action in respect of, any Connecticut state or local governmental
         authority or agency or any United States federal governmental authority
         or agency regulating the banking or trust powers of such Indenture
         Trustee is required for the execution and delivery of, or the carrying
         out by, such Indenture Trustee, of any of the transactions contemplated
         by any of the Fundamental Documents to which such Indenture Trustee is
         or is to be a party, other than any such consent, approval, order,
         authorization, registration, notice or action as has been duly
         obtained, given or taken; and

                           (v) there are no pending or threatened actions or
         proceedings against such Indenture Trustee before any court or
         administrative agency which, if determined adversely to it, would have
         a material adverse effect on the ability of such Indenture Trustee to
         perform its obligations under this Agreement or any other Fundamental
         Document executed by such Indenture Trustee in connection with the
         transactions contemplated by the Fundamental Documents.

                  (b) the Pass Through Trustee represents, warrants and
covenants that:


                                       11
<PAGE>   14

                                              [(2000-2) Note Purchase Agreement]

                           (i) the Pass Through Trustee is a national banking
         association duly organized, validly existing and in good standing under
         the laws of the United States of America, and has the full corporate
         power, authority and legal right under the laws of the State of
         Connecticut and the United States of America pertaining to its banking,
         trust and fiduciary powers to execute and deliver this Agreement and
         each other Fundamental Document to which it is a party and to perform
         its obligations hereunder and thereunder;

                           (ii) this Agreement and each other Fundamental
         Document to which the Pass Through Trustee is a party have been duly
         authorized, executed and delivered by the Pass Through Trustee; this
         Agreement and each other Fundamental Document to which the Pass Through
         Trustee is a party constitute the legal, valid and binding obligations
         of the Pass Through Trustee enforceable against it in accordance with
         their respective terms, except as the same may be limited by applicable
         bankruptcy, insolvency, reorganization, moratorium or similar laws
         affecting the rights of creditors generally and by general principles
         of equity, whether considered in a proceeding at law or in equity;

                           (iii) none of the execution, delivery and performance
         by the Pass Through Trustee of this Agreement or any other Fundamental
         Document to which the Pass Through Trustee is a party, the purchase by
         the Pass Through Trustee of the Notes pursuant to this Agreement, or
         the issuance and sale of the Pass Through Certificates pursuant to the
         Pass Through Trust Agreements, and the Purchase Agreements, contravenes
         any law, rule or regulation of the State of Connecticut or any United
         States governmental authority or agency regulating the Pass Through
         Trustee's banking, trust or fiduciary powers or any judgment or order
         applicable to or binding on the Pass Through Trustee and do not
         contravene or result in any breach of, or constitute a default under,
         the Pass Through Trustee's charter or by-laws or any agreement or
         instrument to which the Pass Through Trustee is a party or by which it
         or any of its properties may be bound;

                           (iv) neither the execution and delivery by the Pass
         Through Trustee of this Agreement or any of the other Fundamental
         Documents to which the Pass Through Trustee is a party, nor the
         consummation by the Pass Through Trustee of any of the transactions
         contemplated hereby or thereby, requires the consent or approval of,
         the giving of notice to, the registration with, or the taking of any
         other action with respect to, any Connecticut governmental authority or
         agency or any Federal governmental authority or agency regulating the
         Pass Through Trustee's banking, trust or fiduciary powers;

                           (v) there are no Taxes payable by the Pass Through
         Trustee imposed by the State of Connecticut or any political
         subdivision or taxing authority thereof in connection with the
         execution, delivery and performance by the Pass Through Trustee of this
         Agreement or any other Fundamental Document to which the Pass Through
         Trustee


                                       12
<PAGE>   15

                                              [(2000-2) Note Purchase Agreement]

         is a party (other than franchise or other taxes based on or measured by
         any fees or compensation received by the Pass Through Trustee for
         services rendered in connection with the transactions contemplated by
         the Pass Through Trust Agreements), and there are no Taxes payable by
         the Pass Through Trustee imposed by the State of Connecticut or any
         political subdivision thereof in connection with the acquisition,
         possession or ownership by the Pass Through Trustee of any of the Notes
         (other than franchise or other taxes based on or measured by any fees
         or compensation received by the Pass Through Trustee for services
         rendered in connection with the transactions contemplated by the Pass
         Through Trust Agreements);

                           (vi) there are no pending or threatened actions or
         proceedings against the Pass Through Trustee before any court or
         administrative agency which individually or in the aggregate, if
         determined adversely to it, would have a material adverse effect on the
         ability of the Pass Through Trustee to perform its obligations under
         this Agreement or any other Fundamental Document to which the Pass
         Through Trustee is a party;

                           (vii) except for the issue and sale of the Notes
         contemplated hereby, the Pass Through Trustee has not directly or
         indirectly offered any Notes for sale to any Person or solicited any
         offer to acquire any Notes from any Person, nor has the Pass Through
         Trustee authorized anyone to act on its behalf to offer directly or
         indirectly any Note for sale to any Person, or to solicit any offer to
         acquire any Note from any Person; and the Pass Through Trustee is not
         in default under any Pass Through Trust Agreement; and

                           (viii) the Pass Through Trustee is not directly or
         indirectly controlling, controlled by or under common control with
         United.

                  (c) the Subordination Agent represents, warrants and
covenants that:

                           (i) the Subordination Agent is a national banking
         association duly organized, validly existing and in good standing under
         the laws of the United States of America, and has the full corporate
         power, authority and legal right under the laws of the State of
         Connecticut and the United States of America pertaining to its banking,
         trust and fiduciary powers to execute and deliver this Agreement and
         each other Fundamental Document to which it is a party and to perform
         its obligations hereunder and thereunder;

                           (ii) this Agreement and each other Fundamental
         Document to which it is a party have been duly authorized, executed and
         delivered by the Subordination Agent; this Agreement and each other
         Fundamental Document to which it is a party constitute the legal, valid
         and binding obligations of the Subordination Agent enforceable against
         it in accordance with their respective terms, except as the same may be
         limited by

                                       13
<PAGE>   16

                                              [(2000-2) Note Purchase Agreement]

         applicable bankruptcy, insolvency, reorganization, moratorium or
         similar laws affecting the rights of creditors generally and by general
         principles of equity, whether considered in a proceeding at law or in
         equity;

                           (iii) none of the execution, delivery and performance
         by the Subordination Agent of this Agreement or any other Fundamental
         Document to which the Subordination Agent is a party contravene any
         law, rule or regulation of the State of Connecticut or any United
         States governmental authority or agency regulating the Subordination
         Agent's banking, trust or fiduciary powers or any judgment or order
         applicable to or binding on the Subordination Agent and does not
         contravene or result in any breach of, or constitute a default under,
         the Subordination Agent's charter or by-laws or any agreement or
         instrument to which the Subordination Agent is a party or by which it
         or any of its properties may be bound;

                           (iv) neither the execution and delivery by the
         Subordination Agent of this Agreement or any other Fundamental Document
         to which the Subordination Agent is a party nor the consummation by the
         Subordination Agent of any of the transactions contemplated hereby or
         thereby requires the consent or approval of, the giving of notice to,
         the registration with, or the taking of any other action with respect
         to, any Connecticut governmental authority or agency or any federal
         governmental authority or agency regulating the Subordination Agent's
         banking, trust or fiduciary powers;

                           (v) there are no Taxes payable by the Subordination
         Agent imposed by the State of Connecticut or any political subdivision
         or taxing authority thereof in connection with the execution, delivery
         and performance by the Subordination Agent of this Agreement or any
         other Fundamental Document to which the Subordination Agent is a party
         (other than franchise or other taxes based on or measured by any fees
         or compensation received by the Subordination Agent for services
         rendered in connection with the transactions contemplated by the
         Intercreditor Agreement or any Liquidity Facility), and there are no
         Taxes payable by the Subordination Agent imposed by the State of
         Connecticut or any political subdivision thereof in connection with the
         acquisition, possession or ownership by the Subordination Agent of any
         of the Notes (other than franchise or other taxes based on or measured
         by any fees or compensation received by the Subordination Agent for
         services rendered in connection with the transactions contemplated by
         the Intercreditor Agreement or any Liquidity Facility);

                           (vi) there are no pending or threatened actions or
         proceedings against the Subordination Agent before any court or
         administrative agency which individually or in the aggregate, if
         determined adversely to it, would materially adversely affect the
         ability of the Subordination Agent to perform its obligations under
         this Agreement or any other Fundamental Document to which the
         Subordination Agent is a party;


                                       14
<PAGE>   17
                                              [(2000-2) Note Purchase Agreement]

                           (vii) the Subordination Agent has not directly or
         indirectly offered any Notes for sale to any Person or solicited any
         offer to acquire any Notes from any Person, nor has the Subordination
         Agent authorized anyone to act on its behalf to offer directly or
         indirectly any Note for sale to any Person, or to solicit any offer to
         acquire any Note from any Person; and the Subordination Agent is not in
         default under any Liquidity Facility; and

                           (viii) the Subordination Agent is not directly or
         indirectly controlling, controlled by or under common control with
         United.

         SECTION 6. Notices. Unless otherwise specifically provided herein, all
notices required or permitted by the terms of this Agreement shall be in English
and in writing, and any such notice shall become effective five days after being
deposited in the United States mail, with proper postage for first-class
registered or certified mail prepaid, or when delivered personally or, if
promptly confirmed by mail as provided above, when dispatched by facsimile or
other written telecommunication, addressed, if to United, the Pass Through
Trustee, the Subordination Agent or any Indenture Trustee, at their respective
addresses or facsimile numbers set forth on Schedule 1.

         SECTION 7. Expenses. All of the reasonable out-of-pocket costs, fees
and expenses incurred by the Pass Through Trustee, the Subordination Agent, the
Liquidity Provider and the Indenture Trustees in connection with the
transactions contemplated by this Agreement shall be paid on or prior to the
Closing Date by United on a net after-tax basis.

         SECTION 8. Miscellaneous. (a) Provided that the transactions
contemplated hereby have been consummated, and except as otherwise provided for
herein, the representations, warranties and agreements herein of United, each
Indenture Trustee, the Subordination Agent and the Pass Through Trustee, and
United's, each Indenture Trustee's, the Subordination Agent's and the Pass
Through Trustee's obligations hereunder, shall survive the expiration or other
termination of this Agreement and the other agreements referred to herein.

                  (b) This Agreement may be executed in any number of
counterparts and each counterpart of this Agreement, including a signature page
executed by each of the parties hereto, shall be an original counterpart of this
Agreement, but all of such counterparts together shall constitute one
instrument. Neither this Agreement nor any of the terms hereof may be
terminated, amended or waived orally, but only by an instrument in writing
signed by the party against which the enforcement of the termination, amendment
or waiver is sought; and no such termination, amendment or waiver shall be
effective unless a signed copy thereof shall have been delivered to each
Indenture Trustee. The table of contents preceding this Agreement and the
headings of the various Sections of this Agreement are for convenience of
reference only and


                                       15
<PAGE>   18

                                              [(2000-2) Note Purchase Agreement]

shall not modify, define, expand or limit any of the terms or provisions hereof.
The terms of this Agreement shall be binding upon, and shall inure to the
benefit of, United and its successors and permitted assigns, the Pass Through
Trustee and its successors as Pass Through Trustee (and any additional trustee
properly appointed) under any of the Trust Supplements, any Indenture Trustee
and its successors as Indenture Trustee (and any additional Indenture Trustee
properly appointed) under any Indenture and the Subordination Agent and its
successors as Subordination Agent under the Intercreditor Agreement.

                  (c) This Agreement is not intended to, and shall not, provide
any Person not a party hereto with any rights of any nature whatsoever against
any of the parties hereto, and no Person not a party hereto shall have any
right, power or privilege in respect of, or have any benefit or interest arising
out of, this Agreement; provided, however, that each of the parties hereto
agrees and acknowledges that the Liquidity Provider shall be a third party
beneficiary of each of the representations and warranties made herein by such
party, and that the Liquidity Provider may rely on such representations and
warranties to the same extent as if such representations and warranties were
made to the Liquidity Provider directly. The terms of this Agreement shall inure
to the benefit of the Liquidity Provider, its successors and permitted assigns.

                  (d) THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK (WITHOUT REGARD TO THE
PRINCIPLES OF CONFLICTS OF LAWS THEREOF (OTHER THAN SECTION 5-1401 OF THE NEW
YORK GENERAL OBLIGATIONS LAW)), AND THE OBLIGATIONS, RIGHTS AND REMEDIES OF THE
PARTIES UNDER THIS AGREEMENT SHALL BE DETERMINED IN ACCORDANCE WITH SUCH LAWS.

                  (e) Each of the parties hereto hereby irrevocably and
unconditionally:

                           (i) submits for itself and its property in any legal
         action or proceeding relating to this Agreement or any other
         Fundamental Document, or for recognition and enforcement of any
         judgment in respect hereof or thereof, to the non-exclusive general
         jurisdiction of the courts of the State of New York, the courts of the
         United States of America for the Southern District of New York, and the
         appellate courts from any thereof;

                           (ii) consents that any such action or proceeding may
         be brought in such courts, and waives any objection that it may now or
         hereafter have to the venue of any such action or proceeding in any
         such court or that such action or proceeding was brought in an
         inconvenient court and agrees not to plead or claim the same;


                                       16
<PAGE>   19

                                              [(2000-2) Note Purchase Agreement]

                           (iii) agrees that service of process in any such
         action or proceeding may be effected by mailing a copy thereof by
         registered or certified mail (or any substantially similar form and
         mail, postage prepaid, to each party hereto at its address set forth in
         Schedule I, or at such other address of which the other Person shall
         have been notified pursuant thereto; and

                           (iv) agrees that nothing herein shall affect the
         right to effect service of process in any other manner permitted by law
         or shall limit the right to sue in any other jurisdiction.

                  (f) EACH OF THE PARTIES HERETO HEREBY AGREES TO WAIVE ITS
RESPECTIVE RIGHTS TO A JURY TRIAL OF ANY CLAIM OR CAUSE OF ACTION BASED UPON OR
ARISING OUT OF THIS AGREEMENT OR ANY DEALINGS BETWEEN THEM RELATING TO THE
SUBJECT MATTER OF THIS AGREEMENT AND THE RELATIONSHIP THAT IS BEING ESTABLISHED,
including contract claims, tort claims, breach of duty claims and all other
common law and statutory claims. Each of the parties warrants and represents
that it has reviewed this waiver with its legal counsel, and that it knowingly
and voluntarily waives its jury trial rights following consultation with such
legal counsel. THIS WAIVER IS IRREVOCABLE, AND CANNOT BE MODIFIED EITHER ORALLY
OR IN WRITING, AND THIS WAIVER SHALL APPLY TO ANY SUBSEQUENT AMENDMENTS,
RENEWALS, SUPPLEMENTS OR MODIFICATIONS TO THIS AGREEMENT.

                            [signature pages follow]




                                       17
<PAGE>   20

                                              [(2000-2) Note Purchase Agreement]

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed by their respective officers thereunto duly authorized as of the
day and year first above written.


                                 UNITED AIR LINES, INC.



                                 By: /s/ JEFFREY T. KAWALSKY
                                     -------------------------------------------
                                     Name: Jeffrey T. Kawalsky
                                     Title: Assistant Treasurer



                                 STATE STREET BANK AND TRUST
                                 COMPANY OF CONNECTICUT, NATIONAL
                                 ASSOCIATION, not in its individual capacity,
                                 except as otherwise provided herein, but solely
                                 as Indenture Trustee, Pass Through Trustee and
                                 Subordination Agent



                                 By: /s/ JOHN G. CORREIA
                                     -------------------------------------------
                                     Name: John G. Correia
                                     Title: Assistant Vice President






                                   18
<PAGE>   21


                                              [(2000-2) Note Purchase Agreement]


                                  SCHEDULE I to
                             Note Purchase Agreement

                     NAMES; ADDRESSES AND WIRE INSTRUCTIONS

UNITED:

Address for Notices:

    If by U.S. Mail
    United Air Lines, Inc.
    P.O. Box 66100
    WHQFT
    Chicago, IL 60666
    Attention: Vice President and Treasurer
    Telecopy: (847) 700-7117

    If by Overnight Delivery Service

    United Air Lines, Inc.
    1200 East Algonquin Road
    WHQFT
    Elk Grove Township, IL 60007
    Attention: Vice President and Treasurer
    Telecopy: (847) 700-7117

PASS THROUGH TRUSTEE, SUBORDINATION AGENT AND INDENTURE TRUSTEE:

Address for Notices:

State Street Bank and Trust Company
of Connecticut, National Association
225 Asylum Street
Goodwin Square
Hartford, Connecticut 06103
Attention: Corporate Trust Division
Telecopy: (860) 244-1881

and


<PAGE>   22


                                              [(2000-2) Note Purchase Agreement]


State Street Bank and Trust Company
of Connecticut, National Association
c/o 2 Avenue de Lafayette, 6th Floor
Boston, Massachusetts 02111-1724
Attention: Corporate Trust
Telecopy: (617) 662-1465






                                       I-2
<PAGE>   23


                                              [(2000-2) Note Purchase Agreement]

                                 SCHEDULE II to
                             Note Purchase Agreement

                                     NOTES,
                          PURCHASERS AND PURCHASE PRICE



<TABLE>
<CAPTION>
Series                     Purchaser            Interest Rate  Principal Amount
------                     ---------            -------------  ----------------
<S>               <C>                           <C>            <C>
Series A-1 Notes  2000-2A-1 Pass Through Trust      7.032%       $349,873,000
Series A-2 Notes  2000-2A-2 Pass Through Trust      7.186%       $732,770,000
Series B Notes    2000-2B Pass Through Trust        7.811%       $271,585,000
Series C Notes    2000-2C Pass Through Trust        7.762%       $151,439,000
</TABLE>