<PAGE>

                                                                     Exhibit 4.4





                          REVOLVING CREDIT AGREEMENT

                          dated as of August 22, 2001

                                    between

                      STATE STREET BANK AND TRUST COMPANY
                     OF CONNECTICUT, NATIONAL ASSOCIATION,

                            as Subordination Agent,
                         as agent and trustee for the
                  United Airlines 2001-1B Pass Through Trust,
                                  as Borrower

                     WESTDEUTSCHE LANDESBANK GIROZENTRALE,
                      acting through its New York branch,

                             as Liquidity Provider

                                  Relating to

                     ____________________________________

                  United Airlines 2001-1B Pass Through Trust
      United Airlines Enhanced Pass Through Certificates, Series 2001-1B

                     ____________________________________


<PAGE>

                               TABLE OF CONTENTS
                               -----------------

<TABLE>
<CAPTION>
<S>                                                                                                              <C>
Article I             DEFINITIONS.............................................................................   1

         Section 1.01          Certain Defined Terms..........................................................   1

Article II            AMOUNT AND TERMS OF THE COMMITMENT......................................................   7

         Section 2.01          Advances.......................................................................   7

         Section 2.02          Making the Advances............................................................   7

         Section 2.03          Fees...........................................................................   9

         Section 2.04          Automatic Reductions and Termination of the Maximum Commitment.................   9

         Section 2.05          Repayments of Interest Advances or the Final Advance...........................   9

         Section 2.06          Repayments of Provider Advances................................................  10

         Section 2.07          Payments to the Liquidity Provider Under the Intercreditor Agreement...........  11

         Section 2.08          Book Entries...................................................................  11

         Section 2.09          Payments from Available Funds Only.............................................  11

         Section 2.10          Extension of Expiry Date.......................................................  11

Article III           OBLIGATIONS OF THE BORROWER.............................................................  12

         Section 3.01          Increased Costs................................................................  12

         Section 3.02          Capital Adequacy...............................................................  13

         Section 3.03          Payments Free of Deductions....................................................  13

         Section 3.04          Payments.......................................................................  14

         Section 3.05          Computations...................................................................  15

         Section 3.06          Payment on Non-Business Days...................................................  15

         Section 3.07          Interest.......................................................................  15

         Section 3.08          Replacement of Borrower........................................................  16

         Section 3.09          Funding Loss Indemnification...................................................  16

         Section 3.10          Illegality.....................................................................  17

Article IV            CONDITIONS PRECEDENT....................................................................  17

         Section 4.01          Conditions Precedent to Effectiveness of Section 2.01..........................  17

         Section 4.02          Conditions Precedent to Borrowing..............................................  19

Article V             COVENANTS...............................................................................  19

         Section 5.01          Affirmative Covenants of the Borrower..........................................  19

         Section 5.02          Negative Covenants of the Borrower.............................................  19
</TABLE>

                                       i
<PAGE>

<TABLE>
<S>                                                                                                             <C>
Article VI            LIQUIDITY EVENTS OF DEFAULT.............................................................  19

         Section 6.01          Liquidity Events of Default....................................................  19

Article VII           MISCELLANEOUS...........................................................................  20

         Section 7.01          Amendments, Etc................................................................  20

         Section 7.02          Notices, Etc...................................................................  20

         Section 7.03          No Waiver; Remedies............................................................  21

         Section 7.04          Further Assurances.............................................................  21

         Section 7.05          Indemnification; Survival of Certain Provisions................................  21

         Section 7.06          Liability of the Liquidity Provider............................................  22

         Section 7.07          Costs, Expenses and Taxes......................................................  22

         Section 7.08          Binding Effect; Participations.................................................  23

         Section 7.09          Severability...................................................................  24

         Section 7.10          GOVERNING LAW..................................................................  24

         Section 7.11          Submission to Jurisdiction; Waiver of Jury Trial; Waiver of Immunity...........  24

         Section 7.12          Execution in Counterparts......................................................  25

         Section 7.13          Entirety.......................................................................  25

         Section 7.14          Headings.......................................................................  25

         Section 7.15          LIQUIDITY PROVIDER'S OBLIGATION TO MAKE ADVANCES...............................  25
</TABLE>

Annex I        Interest Advance Notice of Borrowing
Annex II       Non-Extension Advance Notice of Borrowing
Annex III      Downgrade Advance Notice of Borrowing
Annex IV       Final Advance Notice of Borrowing
Annex V        Notice of Termination
Annex VI       Notice of Replacement Subordination Agent

                                      ii
<PAGE>

                          REVOLVING CREDIT AGREEMENT

     This REVOLVING CREDIT AGREEMENT, dated as of August 22, 2001 (as it may be
amended, supplemented or otherwise modified from time to time in accordance with
the terms hereof, this "Agreement"), between STATE STREET BANK AND TRUST COMPANY
OF CONNECTICUT, NATIONAL ASSOCIATION, a national banking association, not in its
individual capacity but solely as Subordination Agent under the Intercreditor
Agreement (each as defined below), as agent and trustee for the Class B Trust
(as defined below) (the "Borrower"), and WESTDEUTSCHE LANDESBANK GIROZENTRALE, a
German banking institution organized under the laws of the State of North Rhine
- Westphalia, Germany, acting through its New York branch ("West LB")
("Liquidity Provider").

                             W I T N E S S E T H:
                             - - - - - - - - - -

     WHEREAS, pursuant to the Class B Trust Agreement (as defined below), the
Class B Trust is issuing the Class B Certificates; and

     WHEREAS, the Borrower, in order to support the timely payment of a portion
of the interest on the Class B Certificates in accordance with their terms, has
requested the Liquidity Provider to enter into this Agreement, providing in part
for the Borrower to request in specified circumstances that Advances be made
hereunder.

     NOW, THEREFORE, in consideration of the mutual promises contained herein,
and of other good and valuable consideration the receipt and adequacy of which
are hereby acknowledged, the parties hereto agree as follows:

                                   ARTICLE I

                                  DEFINITIONS

     SECTION 1.01   Certain Defined Terms. (a) For all purposes of this
                    ---------------------
Agreement, except as otherwise expressly provided or unless the context
otherwise requires:

                    (i)   The terms used herein that are defined in this Article
     I have the meanings assigned to them in this Article I, and include the
     plural as well as the singular;

                    (ii)  all references in this Agreement to designated
     "Articles," "Sections" and other subdivisions are to the designated
     Articles, Sections and other subdivisions of this Agreement;

                    (iii) the words "herein," "hereof" and "hereunder" and other
     words of similar import refer to this Agreement as a whole and not to any
     particular Article, Section or other subdivision; and

                    (iv)  the term "including" means "including without
     limitation".

          "Additional Costs" has the meaning specified in Section 3.01.
<PAGE>

                                                    [Revolving Credit Agreement]


          "Advance" means an Interest Advance, a Final Advance, a Provider
Advance or an Applied Provider Advance, as the case may be.

          "Applicable Liquidity Rate" has the meaning specified in Section
3.07(g).

          "Applicable Margin" means, with respect to any Unpaid Advance or
Applied Provider Advance, 1.5%.

          "Applied Downgrade Advance" has the meaning specified in Section
2.06(a).

          "Applied Non-Extension Advance" has the meaning assigned to such term
in Section 2.06(a).

          "Applied Provider Advance" has the meaning assigned to such term in
Section 2.06(a).

          "Base Rate" means a fluctuating interest rate per annum in effect from
time to time, which rate per annum shall at all times be equal to the weighted
average of the rates on overnight Federal funds transactions with members of the
Federal Reserve System arranged by Federal funds brokers, as published for each
day in the period for which the Base Rate is to be determined (or, if such day
is not a Business Day, for the preceding Business Day) by the Federal Reserve
Bank of New York, or if such rate is not so published for any day that is a
Business Day, the average of the quotations for such day for such transactions
received by the Liquidity Provider from three Federal funds brokers of
recognized standing selected by it, plus one-quarter of one percent (.25%).

          "Base Rate Advance" means an Advance that bears interest at a rate
based upon the Base Rate.

          "Borrower" has the meaning specified in the recitals to this
Agreement.

          "Borrowing" means the making of Advances requested by delivery of a
Notice of Borrowing.

          "Business Day" means any day (x) other than a Saturday or Sunday or a
day on which commercial banks are authorized or required by law to close in
Chicago, Illinois, New York, New York or the city and state in which the Class B
Trustee, the Subordination Agent or any Indenture Trustee maintains its
corporate trust office or receives and disburses funds, and (y) if the
applicable Business Day relates to any Advance or amount bearing interest based
on LIBOR, on which dealings are carried on in the London interbank market.

          "Consent Period" has the meaning specified in Section 2.10.

          "Downgrade Advance" means an Advance made pursuant to Section 2.02(c).

          "Effective Date" has the meaning specified in Section 4.01.  The
delivery of the certificate of the Liquidity Provider contemplated by Section
4.01(e) shall be conclusive evidence that the Effective Date has occurred.

                                       2
<PAGE>

                                                    [Revolving Credit Agreement]


          "Excluded Taxes" means (i) any Taxes imposed on, based on, or measured
by the overall net income, capital, franchises, or receipts (other than Taxes
which are or are in the nature of sales or use Taxes or value added Taxes) of
the Liquidity Provider or any of its Lending Offices, (ii) withholding Taxes
imposed under laws in effect on the date hereof by the United States on payments
to a recipient in the jurisdiction in which the Liquidity Provider's initial
Lending Office is located, and (iii) withholding Taxes imposed by the United
States on payments to a recipient in any other jurisdiction to which such
Lending Office is moved if, under the laws in effect at the time of such move,
such laws would require greater withholding of Taxes on payments to such
Liquidity Provider acting from an office in such jurisdiction than would be
required on payments to such Liquidity Provider acting from an office in the
jurisdiction from which such Lending Office was moved.

          "Expenses" means liabilities, obligations, damages, settlements,
penalties, claims, actions, suits, costs, expenses, and disbursements
(including, without limitation, reasonable fees and disbursements of legal
counsel and costs of investigation), provided that Expenses shall not include
Taxes.

          "Expiry Date" means August 20, 2002, initially, or any date to which
the Expiry Date is extended pursuant to Section 2.10.

          "Final Advance" means an Advance made pursuant to Section 2.02(d).

          "Indenture Trustee" means, with respect to any Indenture, the
Indenture Trustee thereunder.

          "Intercreditor Agreement" means the Intercreditor Agreement, dated as
of August 22, 2001 between the Trustee, the Liquidity Provider, the liquidity
provider under each Liquidity Facility (other than this Agreement) and the
Subordination Agent, as the same may be amended, supplemented or otherwise
modified from time to time in accordance with its terms.

          "Interest Advance" means an Advance made pursuant to Section 2.02(a).

          "Interest Period" means, with respect to any LIBOR Advance, each of
the following periods:

          (1)  the period beginning on the third Business Day following either
     (x) the Liquidity Provider's receipt of the Notice of Borrowing for such
     LIBOR Advance or (y) the withdrawal of funds from the Class B Cash
     Collateral Account for the purpose of paying interest on the Class B
     Certificates as contemplated by Section 2.06(a) hereof and, in either case,
     ending on the next Regular Distribution Date; and

          (2)  each subsequent period commencing on the last day of the
     preceding Interest Period and ending on the next Regular Distribution Date;

provided, however, that if (x) the Final Advance shall have been made, or (y)
--------  -------
other outstanding Advances shall have been converted into the Final Advance,
then the Interest Periods shall be successive periods of one month beginning on
the third Business Day following the Liquidity Provider's receipt of the Notice
of Borrowing for such Final Advance (in the case of clause (x)

                                       3
<PAGE>

                                                    [Revolving Credit Agreement]


above) or the Regular Distribution Date following such conversion (in the case
of clause (y) above).

          "Lending Office" means the lending office of the Liquidity Provider,
presently located at New York, New York, or such other lending office as the
Liquidity Provider from time to time shall notify the Borrower as its lending
office hereunder.

          "LIBOR" means, with respect to any Interest Period, the interest rate
per annum at which deposits in United States dollars are offered to prime banks
in the London interbank market as indicated on display page 3750 (British
Bankers Association-LIBOR) of the Dow Jones Markets Service (or such other page
as may replace such display page 3750 for the purpose of displaying London
interbank offered rates for United States dollar deposits) or, if not so
indicated, the average (rounded upwards to the nearest 1/16%), as determined by
the Liquidity Provider, of such rates as indicated on the Reuters Screen LIBO
Page (or such other page as may replace such Reuters Screen LIBO Page for the
purpose of displaying London interbank offered rates for United States dollar
deposits) or, if neither such alternative is indicated, the average (rounded
upwards to the nearest 1/16%), as determined by the Liquidity Provider, of such
rates offered by the London Reference Banks to prime banks in the London
interbank market, in each case at or about 11:00 a.m. (London time) on the day
two LIBOR Business Days prior to the first day of such Interest Period for
deposits of a duration equal to such Interest Period (or such other period most
nearly corresponding to such period) in an amount substantially equal to the
principal amount of the applicable LIBOR Advance as of the first day of such
Interest Period.  The Liquidity Provider will, if necessary, request that each
of the London Reference Banks provide a quotation of its rate.  If at least two
such quotations are provided, the rate will be the average of the quotations
(rounded upwards to the nearest 1/100%).  If no such quotation can be obtained,
the rate will be Base Rate.

          "LIBOR Advance" means an Advance bearing interest at a rate based upon
LIBOR.

          "Liquidity Event of Default" means the occurrence of either (a) the
Acceleration of all of the Equipment Notes or (b) a United Bankruptcy Event.

          "Liquidity Indemnitee" means (i) the Liquidity Provider, (ii) the
directors, officers, employees, servants and agents of the Liquidity Provider,
and (iii) the successors and permitted assigns of the persons described in
clauses (i) through (ii), inclusive.

          "Liquidity Provider" has the meaning specified in the recital of
parties to this Agreement.

          "London Reference Banks" means the principal London offices of
Westdeutsche Landesbank Girozentrale, the Mitsubishi Trust and Banking
Corporation and ABN AMRO Bank N.V., or such other bank or banks as may from time
to time be agreed to by United and the Liquidity Provider.

          "Maximum Available Commitment" shall mean, subject to the proviso
contained in the third sentence of Section 2.02(a), at any time of
determination, (a) the Maximum Commitment at such time, less (b) the aggregate
amount of each Interest Advance outstanding at

                                       4
<PAGE>

                                                    [Revolving Credit Agreement]


such time; provided, however, that following a Provider Advance or a Final
           --------  -------
Advance, the Maximum Available Commitment shall be zero.

          "Maximum Commitment" means initially $15,874,710, as the same may be
reduced from time to time in accordance with Section 2.04(a).

          "Non-Excluded Tax" has the meaning specified in Section 3.03.

          "Non-Extension Advance" means an Advance made pursuant to Section
2.02(b).

          "Notice of Borrowing" has the meaning specified in Section 2.02(e).

          "Notice of Replacement Subordination Agent" has the meaning specified
in Section 3.08.

          "Participating Institution" has the meaning specified in Section
7.08(b).

          "Participation Agreement" means, with respect to each Indenture, the
"Participation Agreement" referred to therein.

          "Performing Equipment Note Deficiency" means any time that less than
65% of the then aggregate outstanding principal amount of all Equipment Notes
are Performing Equipment Notes.

          "Prospectus Supplement" means the Prospectus Supplement dated August
10, 2001, relating to the Certificates, as such Prospectus Supplement may be
amended or supplemented.

          "Provider Advance" means a Downgrade Advance or a Non-Extension
Advance.

          "Regulatory Change" has the meaning specified in Section 3.01.

          "Replenishment Amount" has the meaning assigned to such term in
Section 2.06(b).

          "Required Amount" means, for any day, the sum of the aggregate amount
of interest, calculated at the rate per annum equal to the Stated Interest Rate
for the Class B Certificates on the basis of a 360-day year comprised of twelve
30-day months, that would be payable on the Class B Certificates on each of the
three successive semiannual Regular Distribution Dates following such day or, if
such day is a Regular Distribution Date, on such day and the succeeding two
semiannual Regular Distribution Dates, in each case calculated on the basis of
the Pool Balance of the Class B Certificates on such day and without regard to
expected future payments of principal on the Class B Certificates.

          "Termination Date" means the earliest to occur of the following:  (i)
the Expiry Date; (ii) the date on which the Borrower delivers to the Liquidity
Provider a certificate, signed by a Responsible Officer of the Borrower,
certifying that all of the Class B Certificates have been paid in full (or
provision has been made for such payment in accordance with

                                       5
<PAGE>

                                                    [Revolving Credit Agreement]

the Intercreditor Agreement and the Trust Agreement) or are otherwise no longer
entitled to the benefits of this Agreement; (iii) the date on which the Borrower
delivers to the Liquidity Provider a certificate, signed by a Responsible
Officer of the Borrower, certifying that a Replacement Liquidity Facility has
been substituted for this Agreement in full pursuant to Section 3.6(e) of the
Intercreditor Agreement; (iv) the fifth Business Day following the receipt by
the Borrower and United of a Termination Notice from the Liquidity Provider
pursuant to Section 6.01; and (v) the date on which no Advance is or may
(including by reason of reinstatement as herein provided) become available for a
Borrowing hereunder.

          "Termination Notice" means the Notice of Termination substantially in
the form of Annex V to this Agreement.

          "Unapplied Downgrade Advance" means any Downgrade Advance other than
an Applied Downgrade Advance.

          "Unapplied Non-Extension Advance" means any Non-Extension Advance
other than an Applied Non-Extension Advance.

          "Unapplied Provider Advance" means any Provider Advance other than an
Applied Provider Advance.

          "Unpaid Advance" has the meaning specified in Section 2.05.

          "Withdrawal Notice" has the meaning specified in Section 2.10.

          (b)  Terms Defined in the Intercreditor Agreement. For all purposes of
this Agreement, the following terms shall have the respective meanings assigned
to such terms in the Intercreditor Agreement:

     "Acceleration," "Additional Payments," "Affiliate," "Certificates," "Class
     A-1 Certificates," "Class A-2 Certificates," "Class A-3 Certificates,"
     "Class B Cash Collateral Account," "Class B Certificates," "Class B Trust
     ," "Class B Trust Agreement," "Class B Trustee," "Class C Certificates,"
     "Class D Certificates," "Closing Date," "Controlling Party," "Distribution
     Date," "Downgraded Facility," "Indenture," "Notes," "Fee Letter," "Final
     Maturity Date," "Indentures," "Investment Earnings," "Liquidity Facility,"
     "Liquidity Obligations," "Moody's," "Non-Extended Facility," "Note Purchase
     Agreement," "Operative Agreements," "Aircraft", "Participation Agreements,"
     "Performing Equipment Note," "Person," "Pool Balance," "Rating Agency,"
     "Regular Distribution Date," "Replacement Liquidity Facility," "Responsible
     Officer," "Scheduled Payment," "Special Payment," "Standard & Poor's,"
     "Stated Interest Rate," "Subordination Agent," "Taxes," "Threshold Rating,"
     "Triggering Event," "Trust Agreement," "Trustee," "Underwriters,"
     "Underwriting Agreement," "United," "United Bankruptcy Event" and "Written
     Notice."

                                       6
<PAGE>

                                                    [Revolving Credit Agreement]

                                  ARTICLE II

                      AMOUNT AND TERMS OF THE COMMITMENT

     SECTION 2.01   Advances. The Liquidity Provider hereby irrevocably agrees,
                    --------
on the terms and conditions hereinafter set forth, to make Advances to the
Borrower from time to time on any Business Day during the period from the
Effective Date until 12:00 noon (Chicago time) on the Expiry Date (unless the
obligations of the Liquidity Provider shall be earlier terminated in accordance
with the terms of Section 2.04) in an aggregate amount at any time outstanding
not to exceed the Maximum Commitment.

     SECTION 2.02   Making the Advances. (a) Each "Interest Advance" shall be
                    -------------------
made in a single Borrowing by delivery to the Liquidity Provider of a written
and completed Notice of Borrowing in substantially the form of Annex I, signed
by a Responsible Officer of the Borrower, such Interest Advance in an amount not
exceeding the Maximum Available Commitment at such time and shall be used solely
for the payment when due of interest on the Class B Certificates at the Stated
Interest Rate therefor in accordance with Section 3.6(a) of the Intercreditor
Agreement. Each Interest Advance made hereunder shall automatically reduce the
Maximum Available Commitment and the amount available to be borrowed hereunder
by subsequent Advances by the amount of such Interest Advance (subject to
reinstatement as provided in the next sentence). Upon repayment to the Liquidity
Provider in full or in part of the amount of any Interest Advance made pursuant
to this Section 2.02(a), together with accrued interest thereon (as provided
herein), the Maximum Available Commitment shall be reinstated by the amount of
such repaid Interest Advance, but not to exceed the Maximum Commitment;
provided, however, that the Maximum Available Commitment shall not be so
--------  -------
reinstated at any time if (i) a Liquidity Event of Default shall have occurred
and be continuing and (ii) there is a Performing Equipment Note Deficiency.

               (b)  A "Non-Extension Advance" shall be made in a single
Borrowing if this Agreement is not extended in accordance with Section 3.6(d) of
the Intercreditor Agreement (unless a Replacement Liquidity Facility to replace
this Agreement shall have been delivered to the Borrower as contemplated by said
Section 3.6(d) within the time period specified in such Section) by delivery to
the Liquidity Provider of a written and completed Notice of Borrowing in
substantially the form of Annex II attached hereto, signed by a Responsible
Officer of the Borrower, in an amount equal to the Maximum Available Commitment
at such time, and shall be used to fund the Class B Cash Collateral Account in
accordance with said Section 3.6(d) and Section 3.6(f) of the Intercreditor
Agreement.

               (c)  A "Downgrade Advance" shall be made in a single Borrowing
upon a downgrading of the Liquidity Provider's relevant debt rating issued by
either Rating Agency below the applicable Threshold Rating (as provided for in
Section 3.6(c) of the Intercreditor Agreement) unless a Replacement Liquidity
Facility shall have been delivered to the Borrower in accordance with said
Section 3.6(c), by delivery to the Liquidity Provider of a written and completed
Notice of Borrowing in substantially the form of Annex III, signed by a
Responsible Officer of the Borrower, in an amount equal to the Maximum Available
Commitment at such time, and shall be used to fund the Class B Cash Collateral
Account in accordance with said

                                       7
<PAGE>

                                                    [Revolving Credit Agreement]

Section 3.6(c) and Section 3.6(f). Upon such downgrading, the Liquidity Provider
shall promptly deliver notice thereof to the Borrower, the Trustee and United.

          (d)  A "Final Advance" shall be made in a single Borrowing upon the
receipt by the Borrower of a Termination Notice from the Liquidity Provider
pursuant to Section 6.01, by delivery to the Liquidity Provider of a written and
completed Notice of Borrowing in substantially the form of Annex IV, signed by a
Responsible Officer of the Borrower, in an amount equal to the Maximum Available
Commitment at such time, and shall be used to fund the Class B Cash Collateral
Account (in accordance with Section 3.6(f) and Section 3.6(i) of the
Intercreditor Agreement).

          (e)  Each Borrowing shall be made on notice in writing (a "Notice of
Borrowing") in substantially the form required by Section 2.02(a), 2.02(b),
2.02(c) or 2.02(d), as the case may be, given by the Borrower to the Liquidity
Provider. If a Notice of Borrowing is delivered by the Borrower in respect of
any Borrowing no later than 12:00 noon (Chicago time) on a Business Day, upon
satisfaction of the conditions precedent set forth in Section 4.02 with respect
to a requested Borrowing, the Liquidity Provider shall, before 4:00 p.m.
(Chicago time) on the date of such Borrowing or on such later Business Day
specified by the Borrower in such Notice of Borrowing, make available for the
account of its Lending Office, in U.S. dollars and in immediately available
funds, the amount of such Borrowing to be paid to the Borrower in accordance
with its payment instructions. If a Notice of Borrowing is delivered by the
Borrower in respect of any Borrowing after 12:00 noon (Chicago time) on a
Business Day, upon satisfaction of the conditions precedent set forth in Section
4.02 with respect to a requested Borrowing, the Liquidity Provider shall, before
11:00 a.m. (Chicago time) on the first Business Day following the day of receipt
of such Notice of Borrowing or on such later Business Day specified by the
Borrower in such Notice of Borrowing, make available to the Borrower, in
accordance with its payment instructions, in U.S. dollars and in immediately
available funds, the amount of such Borrowing. Payments of proceeds of a
Borrowing shall be made by wire transfer of immediately available funds to the
Borrower in accordance with such wire transfer instructions as the Borrower
shall furnish from time to time to the Liquidity Provider for such purpose. Each
Notice of Borrowing shall be irrevocable and binding on the Borrower. Each
Notice of Borrowing shall be effective upon delivery of a copy thereof to the
Liquidity Provider's New York Branch at the address specified in Section 7.02.

          (f)  Upon the making of any Advance requested pursuant to a Notice of
Borrowing in accordance with the Borrower's payment instructions, the Liquidity
Provider shall be fully discharged of its obligation hereunder with respect to
such Notice of Borrowing, and the Liquidity Provider shall not thereafter be
obligated to make any further Advances hereunder in respect of such Notice of
Borrowing to the Borrower or to any other Person. If the Liquidity Provider
makes an Advance requested pursuant to a Notice of Borrowing before 11:00 a.m.
(Chicago time) on the second Business Day after the date of payment specified in
said Section 2.02(e), the Liquidity Provider shall have fully discharged its
obligations hereunder with respect to such Advance and an event of default shall
not have occurred hereunder. Following the making of any Advance pursuant to
Section 2.02(b), Section 2.02(c) or Section 2.02(d) to fund the Class B Cash
Collateral Account, the Liquidity Provider shall have no interest in or rights
to the Class B Cash Collateral Account, such Advance or any other amounts from
time to time on deposit in the Class B Cash Collateral Account; provided,
                                                                --------
however, that the foregoing
-------

                                       8
<PAGE>

                                                    [Revolving Credit Agreement]


shall not affect or impair the obligations of the Subordination Agent to make
the distributions contemplated by Section 3.6(e) or (f) of the Intercreditor
Agreement and provided further, that the foregoing shall not affect or impair
              -------- -------
the rights of the Liquidity Provider to provide written instructions with
respect to the investment and reinvestment of the Cash Collateral Accounts to
the extent provided in Section 2.2(b) of the Intercreditor Agreement. By paying
to the Borrower proceeds of Advances requested by the Borrower in accordance
with the provisions of this Agreement, the Liquidity Provider makes no
representation as to, and assumes no responsibility for, the correctness or
sufficiency for any purpose of the amount of the Advances so made and requested.

     Section 2.03   Fees. The Borrower agrees to pay to the Liquidity Provider
                    ----
the fees set forth in the Fee Letter.

     Section 2.04   Automatic Reductions and Termination of the Maximum
                    ---------------------------------------------------
Commitment.
----------

               (a)  Automatic Reductions. Promptly following each date on which
                    --------------------
the Required Amount is reduced as a result of a reduction in the Pool Balance of
the Class B Certificates or otherwise, the Maximum Commitment shall
automatically be reduced to an amount equal to such reduced Required Amount (as
calculated by the Borrower). The Borrower shall give notice of any such
automatic reduction of the Maximum Commitment to the Liquidity Provider within
two Business Days thereof. The failure by the Borrower to furnish any such
notice shall not affect such automatic reduction of the Maximum Commitment.

               (b)  Termination. Upon the making of any Provider Advance or
                    -----------
Final Advance hereunder or the occurrence of the Termination Date, the
obligation of the Liquidity Provider to make further Advances hereunder shall
automatically and irrevocably terminate, and the Borrower shall not be entitled
to request any further Borrowing hereunder.

     Section 2.05   Repayments of Interest Advances or the Final Advance.
                    ----------------------------------------------------
Subject to Sections 2.06, 2.07 and 2.09, the Borrower hereby agrees, without
notice of an Advance or demand for repayment from the Liquidity Provider (which
notice and demand are hereby waived by the Borrower), to pay, or to cause to be
paid, to the Liquidity Provider on each date on which the Liquidity Provider
shall make an Interest Advance or the Final Advance, an amount equal to (a) the
amount of such Advance (any such Advance, until repaid, is referred to herein as
an "Unpaid Advance"), plus (b) interest on the amount of each such Unpaid
Advance as provided in Section 3.07; provided, however, that if (i) the
                                     --------  -------
Liquidity Provider shall make a Provider Advance at any time after making one or
more Interest Advances which shall not have been repaid in accordance with this
Section 2.05 or (ii) this Liquidity Facility shall become a Downgraded Facility
or Non-Extended Facility at any time when unreimbursed Interest Advances have
reduced the Maximum Available Commitment to zero, then such Interest Advances
shall cease to constitute Unpaid Advances and shall be deemed to have been
changed into an Applied Downgrade Advance or an Applied Non-Extension Advance,
as the case may be, for all purposes of this Agreement (including, for the
purpose of determining when such Interest Advance is required to be repaid to
the Liquidity Provider in accordance with Section 2.06 and for the purposes of
Section 2.06(b)). The Borrower and the Liquidity Provider agree that the
repayment in full of each Interest Advance and Final Advance on the date such
Advance is made

                                       9
<PAGE>

                                                    [Revolving Credit Agreement]


is intended to be a contemporaneous exchange for new value given to the Borrower
by the Liquidity Provider.

     Section 2.06   Repayments of Provider Advances. (a) Amounts advanced
                    -------------------------------
hereunder in respect of a Provider Advance shall be deposited in the Class B
Cash Collateral Account, invested and withdrawn from the Class B Cash Collateral
Account as set forth in Sections 3.6(c), (d) and (f) of the Intercreditor
Agreement. The Borrower agrees to pay to the Liquidity Provider, on each Regular
Distribution Date, commencing on the first Regular Distribution Date after the
making of a Provider Advance, interest on the principal amount of any such
Provider Advance as provided in Section 3.07; provided, however, that amounts in
                                              --------  -------
respect of a Provider Advance withdrawn from the Class B Cash Collateral Account
for the purpose of paying interest on the Class B Certificates in accordance
with Section 3.6(f) of the Intercreditor Agreement (the amount of any such
withdrawal being (y) in the case of a Downgrade Advance, an "Applied Downgrade
Advance" and (z) in the case of a Non-Extension Advance, an "Applied Non-
Extension Advance" and, together with an Applied Downgrade Advance, an "Applied
Provider Advance") shall thereafter (subject to Section 2.06(b)) be treated as
an Interest Advance under this Agreement for purposes of determining the
Applicable Liquidity Rate for interest payable thereon; and provided, further,
                                                            --------  -------
that if, following the making of a Provider Advance, the Liquidity Provider
delivers a Termination Notice to the Borrower pursuant to Section 6.01, such
Provider Advance shall thereafter be treated as a Final Advance under this
Agreement for purposes of determining the Applicable Liquidity Rate for interest
payable thereon and the obligation for repayment thereof. Subject to Sections
2.07 and 2.09 hereof, immediately upon the withdrawal of any amounts from the
Class B Cash Collateral Account on account of a reduction in the Required
Amount, the Borrower shall repay to the Liquidity Provider a portion of the
Provider Advances in a principal amount equal to the amount of such reduction,
plus interest on the principal amount prepaid as provided in Section 3.07.

               (b)  At any time when an Applied Provider Advance (or any portion
thereof) is outstanding, upon the deposit in the Class B Cash Collateral Account
of any amount pursuant to clause third of Section 2.4(b) of the Intercreditor
Agreement, clause third of Section 3.2 of the Intercreditor Agreement or clause
fourth of Section 3.3 of the Intercreditor Agreement (any such amount being a
"Replenishment Amount") for the purpose of replenishing or increasing the
balance thereof up to the amount of the Required Amount at such time, (i) the
aggregate outstanding principal amount of all Applied Provider Advances (and of
Provider Advances treated as an Interest Advance for purposes of determining the
Applicable Liquidity Rate for interest payable thereon) shall be automatically
reduced by the amount of such Replenishment Amount and (ii) the principal amount
of all outstanding Unapplied Provider Advances shall be automatically increased
by the amount of such Replenishment Amount.

               (c)  Upon the provision of a Replacement Liquidity Facility in
replacement of this Agreement in accordance with Section 3.6(e) of the
Intercreditor Agreement, amounts remaining on deposit in the Class B Cash
Collateral Account after giving effect to any Applied Provider Advance on the
date of such replacement shall be reimbursed to the Liquidity Provider, but only
to the extent such amounts are necessary to repay in full to the Liquidity
Provider all amounts owing to it hereunder.

                                      10
<PAGE>

                                                    [Revolving Credit Agreement]


     Section 2.07   Payments to the Liquidity Provider Under the Intercreditor
                    ---------------------------------------------------------
Agreement.  In order to provide for payment or repayment to the Liquidity
---------
Provider of any amounts hereunder, the Intercreditor Agreement provides that
amounts available and referred to in Articles II and III of the Intercreditor
Agreement, to the extent payable to the Liquidity Provider pursuant to the terms
of the Intercreditor Agreement (including, without limitation, Section 3.6(f) of
the Intercreditor Agreement), shall be paid to the Liquidity Provider in
accordance with the terms thereof.  Amounts so paid to the Liquidity Provider
shall be applied by the Liquidity Provider to Liquidity Obligations then due and
payable in the order of priority required by the applicable provisions of
Articles II and III of the Intercreditor Agreement or, if not provided for in
the Intercreditor Agreement, then in such manner as the Liquidity Provider shall
deem appropriate.

     Section 2.08   Book Entries.  The Liquidity Provider shall maintain in
                    ------------
accordance with its usual practice an account or accounts evidencing the
indebtedness of the Borrower resulting from Advances made from time to time and
the amounts of principal and interest payable hereunder and paid from time to
time in respect thereof; provided, however, that the failure by the Liquidity
                         --------  -------
Provider to maintain such account or accounts shall not affect the obligations
of the Borrower in respect of Advances.

     Section 2.09   Payments from Available Funds Only. All payments to be made
                    ----------------------------------
by the Borrower under this Agreement shall be made only from amounts received by
it that constitute Scheduled Payments or Special Payments or payments under
Section 5(b) of any Participation Agreement and Sections 4(j) and 7 of the Note
Purchase Agreement, and only to the extent that the Borrower shall have
sufficient income or proceeds therefrom to enable the Borrower to make payments
in accordance with the terms hereof after giving effect to the priority of
payments provisions set forth in the Intercreditor Agreement. The Liquidity
Provider agrees that it shall look solely to such amounts to the extent
available for distribution to it as provided in the Intercreditor Agreement and
this Agreement and that the Borrower, in its individual capacity, is not
personally liable to it for any amounts payable or liability under this
Agreement except as expressly provided in this Agreement or the Intercreditor
Agreement. Amounts on deposit in the Class B Cash Collateral Account shall be
available to the Borrower to make payments under this Agreement only to the
extent and for the purposes expressly contemplated in Section 3.6(f) of the
Intercreditor Agreement.

     Section 2.10   Extension of Expiry Date. No earlier than the 60th day and
                    ------------------------
no later than the 40th day prior to the then effective Expiry Date (unless such
Expiry Date is on or after the date that is 15 days after the Final Maturity
Date for the Class B Certificates), the Borrower shall request that the
Liquidity Provider extend the Expiry Date to the earlier of (i) the date that is
15 days after the Final Maturity Date for the Class B Certificates and (ii) the
date that is the day immediately preceding the 364th day occurring after the
last day of the Consent Period (as hereinafter defined). Whether or not the
Borrower has made such request, the Liquidity Provider shall advise the
Borrower, no earlier than the 40th day (or, if earlier, the date of the
Liquidity Provider's receipt of such request, if any, from the Borrower) and no
later than the 25th day prior to the then effective Expiry Date (such period the
"Consent Period"), whether, in its sole discretion, it agrees to so extend the
Expiry Date. If the Liquidity Provider advises the Borrower on or before the
date on which the Consent Period ends that such Expiry Date shall not be so
extended, or fails to irrevocably and unconditionally advise the Borrower on or
before the date on which the Consent Period ends that such Expiry Date shall be
so extended (and, in each case,

                                      11
<PAGE>

                                                    [Revolving Credit Agreement]


if the Liquidity Provider shall not have been replaced in accordance with
Section 3.6(e) of the Intercreditor Agreement), the Borrower shall be entitled
on and after the date on which the Consent Period ends (but prior to the then
effective Expiry Date) to request a Non-Extension Advance in accordance with
Section 2.02(b) and Section 3.6(d) of the Intercreditor Agreement.

                                  ARTICLE III

                          OBLIGATIONS OF THE BORROWER

     Section 3.01   Increased Costs.  The Borrower shall pay to the Liquidity
                    ---------------
Provider from time to time such amounts as may be necessary to compensate the
Liquidity Provider for any costs incurred by the Liquidity Provider which are
attributable to its making or maintaining any Advances hereunder or its
obligation to make any such Advances hereunder, or any reduction in any amount
receivable by the Liquidity Provider under this Agreement or the Intercreditor
Agreement in respect of any such Advances or such obligation (such increases in
costs and reductions in amounts receivable being herein called "Additional
Costs"), resulting from any change after the date of this Agreement in U.S.
federal, state, or municipal, or any foreign laws or regulations, or the
adoption or making after such date of any interpretation, regulation, directive,
guideline, requirement or request whether or not having the force of law, by any
court or governmental or monetary authority charged with the interpretation or
administration thereof (a "Regulatory Change"), which: (1) changes the basis of
taxation of any amounts payable to the Liquidity Provider under this Agreement
in respect of any such Advances or such obligation (other than Taxes); or (2)
imposes or modifies any reserve, special deposit, compulsory loan or similar
requirements relating to any extensions of credit or other assets of, or any
deposits with or other liabilities of, the Liquidity Provider (including any
such Advances or such obligation or any deposits referred to in the definition
of LIBOR or related definitions).  The Liquidity Provider agrees to use
reasonable efforts (consistent with its internal policy and applicable legal and
regulatory restrictions) to change the jurisdiction of its Lending Office if
making such change would avoid the need for, or reduce the amount of, any amount
payable under this Section 3.01 that may thereafter accrue and would not, in the
reasonable judgment of the Liquidity Provider, be otherwise disadvantageous to
the Liquidity Provider.

     The Liquidity Provider shall notify the Borrower of any event occurring
after the date of this Agreement that shall entitle the Liquidity Provider to
compensation pursuant to this Section 3.01 as promptly as practicable after it
obtains knowledge thereof and determines to request such compensation, which
notice shall describe in reasonable detail the calculation of the amounts owed
under this Section 3.01.  Determinations by the Liquidity Provider for purposes
of this Section 3.01 of the effect of any Regulatory Change on its costs of
making or maintaining Advances or on amounts receivable by it in respect of
Advances, and of the additional amounts required to compensate the Liquidity
Provider in respect of any Additional Costs, shall be prima facie evidence of
the amount owed under this Section 3.01.

     Notwithstanding the preceding two paragraphs, (i) the Liquidity Provider
and the Subordination Agent agree that any permitted assignee or participant of
the initial Liquidity Provider that is not a bank shall not be entitled to the
benefits of the preceding two paragraphs (but without limiting the provisions of
Section 7.08 hereof), and (ii) in no event shall the abolition, alteration or
modification of the Gewahrtragerhaftung and the Anstaltslast in

                                      12
<PAGE>

                                                    [Revolving Credit Agreement]


accordance with the European Commissions' Statement of July 17, 2001, as
amended, altered or modified from time to time, in respect of any liabilities of
the Liquidity Provider constitute a Regulatory Change.

     Section 3.02   Capital Adequacy.  If (1) compliance with any judicial,
                    ----------------
administrative or other governmental interpretation of any law or regulation or
(2) compliance by the Liquidity Provider or any corporation controlling the
Liquidity Provider with any guideline or request from any central bank or other
governmental authority (whether or not having the force of law) has the effect
of requiring an increase in the amount of capital required or expected to be
maintained by the Liquidity Provider or any corporation controlling the
Liquidity Provider, and such increase is based upon the Liquidity Provider's
obligations hereunder and other similar obligations, the Borrower shall pay to
the Liquidity Provider such additional amount as shall be reasonably allocable
to the Liquidity Provider's obligations to the Borrower hereunder.  The
Liquidity Provider agrees to use reasonable efforts (consistent with applicable
legal and regulatory restrictions) to change the jurisdiction of its Lending
Office if making such change would avoid the need for, or reduce the amount of,
any amount payable under this Section 3.02 that may thereafter accrue and would
not, in the reasonable judgment of the Liquidity Provider, be otherwise
disadvantageous to the Liquidity Provider.

     The Liquidity Provider shall notify the Borrower of any event occurring
after the date of this Agreement that shall entitle the Liquidity Provider to
compensation pursuant to this Section 3.02 as promptly as practicable after it
obtains knowledge thereof and determines to request such compensation, which
notice shall describe in reasonable detail the calculation of the amounts owed
under this Section 3.02.  Determinations by the Liquidity Provider for purposes
of this Section 3.02 of the effect of any increase in the amount of capital
required to be maintained by the Liquidity Provider and of the amount allocable
to the Liquidity Provider's obligations to the Borrower hereunder shall be prima
facie evidence of the amounts owed under this Section 3.02.

     Notwithstanding the preceding two paragraphs, (i) the Liquidity Provider
and the Subordination Agent agree that any permitted assignee or participant of
the initial Liquidity Provider that is not a bank shall not be entitled to the
benefits of the preceding two paragraphs (but without limiting the provisions of
Section 7.08 hereof), and (ii) in no event shall the abolition, alteration or
modification of the Gewahrtragerhaftung and the Anstaltslast in accordance with
the European Commission's Statement of July 17, 2001, as amended, altered or
modified from time to time, in respect of any liabilities of the Liquidity
Provider give rise to any claim under this Section 3.02.

     Section 3.03   Payments Free of Deductions.  (a)  All payments made by the
                    ---------------------------
Borrower under this Agreement shall be made free and clear of, and without
reduction for or on account of, any Taxes, excluding Excluded Taxes (such non-
excluded taxes being referred to herein, collectively, as "Non-Excluded Taxes").
If any Non-Excluded Taxes are required to be withheld or deducted from any
amounts payable to the Liquidity Provider under this Agreement, the Borrower
shall (i) within the time prescribed therefor by applicable law pay to the
appropriate governmental or taxing authority the full amount of any such Non-
Excluded Taxes (and any additional Non-Excluded Taxes in respect of the payment
required under clause (ii) below) and make such reports or returns in connection
therewith at the time or times and in the manner

                                      13
<PAGE>

                                                    [Revolving Credit Agreement]


prescribed by applicable law, and (ii) pay to the Liquidity Provider an
additional amount which (after deduction of all such Non-Excluded Taxes) shall
be sufficient to yield to the Liquidity Provider the full amount which would
have been received by it had no such withholding or deduction been made. Within
30 days after the date of each payment hereunder, the Borrower shall furnish to
the Liquidity Provider the original or a certified copy of (or other documentary
evidence of) the payment of the Non-Excluded Taxes applicable to such payment.
The Liquidity Provider agrees to use reasonable efforts (consistent with
applicable legal and regulatory restrictions) to change the jurisdiction of its
Lending Office if making such change would avoid the need for, or reduce the
amount of, any such additional amounts that may thereafter accrue and would not,
in the reasonable judgment of the Liquidity Provider, be otherwise materially
disadvantageous (as determined by the Liquidity Provider) to the Liquidity
Provider or require the Liquidity Provider to incur any cost or expenses for
which it is not indemnified by the Borrower. The Liquidity Provider shall
deliver to the Borrower such certificates and documents as may be reasonably
requested by the Borrower and required by applicable law and as may be legally
delivered by the Liquidity Provider to establish that payments hereunder are
exempt from (or entitled to a reduced rate of) withholding Tax.

               (b)  All payments (including, without limitation, Advances) made
by the Liquidity Provider under this Agreement shall be made free and clear of,
and without reduction for or on account of, any Taxes. If any Taxes are required
to be withheld or deducted from any amounts payable to the Borrower under this
Agreement, the Liquidity Provider shall (i) within the time prescribed therefor
by applicable law pay to the appropriate governmental or taxing authority the
full amount of any such Taxes (and any additional Taxes in respect of the
additional amounts payable under clause (ii) hereof) and make such reports or
returns in connection therewith at the time or times and in the manner
prescribed by applicable law, and (ii) pay to the Borrower an additional amount
which (after deduction of all such Taxes) shall be sufficient to yield to the
Borrower the full amount which would have been received by it had no such
withholding or deduction been made. Within 30 days after the date of each
payment hereunder, the Liquidity Provider shall furnish to the Borrower the
original or a certified copy of (or other documentary evidence of) the payment
of the Taxes applicable to such payment.

               (c)  If any exemption from, or reduction in the rate of, any
Taxes is reasonably available to the Borrower to establish that payments under
this Agreement are exempt from (or entitled to a reduced rate of) tax, the
Borrower shall deliver to the Liquidity Provider such form or forms and such
other evidence of the eligibility of the Borrower for such exemption or
reduction as the Liquidity Provider may reasonably identify to the Borrower as
being required as a condition to exemption from, or reduction in the rate of,
any Taxes.

     Section 3.04   Payments.  The Borrower shall make or cause to be made each
                    --------
payment to the Liquidity Provider under this Agreement so as to cause the same
to be received by the Liquidity Provider not later than 1:00 P.M. (Chicago time)
on the day when due.  The Borrower shall make all such payments in lawful money
of the United States of America, to the Liquidity Provider in immediately
available funds, by wire transfer to The Chase Manhattan Bank, New York, ABA No.
021000021, Account Name: Westdeutsche Landesbank Girozentrale, New York Branch,
Account No. 920-1-060663, ref:  United Airlines 2001-1B.

                                      14
<PAGE>

                                                    [Revolving Credit Agreement]


     Section 3.05   Computations. All computations of interest based on the Base
                    ------------
Rate shall be made on the basis of a year of 365 or 366 days, as the case may
be, and all computations of interest based on the LIBOR shall be made on the
basis of a year of 360 days, in each case for the actual number of days
(including the first day but excluding the last day) occurring in the period for
which such interest is payable.

     Section 3.06   Payment on Non-Business Days. Whenever any payment to be
                    ----------------------------
made hereunder shall be stated to be due on a day other than a Business Day,
such payment shall be made on the next Business Day and no additional interest
shall be due as a result (and if so made, shall be deemed to have been made when
due). If any payment in respect of interest on an Advance is so deferred to the
next Business Day, such deferral shall not delay the commencement of the next
Interest Period for such Advance (if such Advance is a LIBOR Advance) or reduce
the number of days for which interest shall be payable on such Advance on the
next interest payment date for such Advance.

     Section 3.07   Interest. (a) Subject to Section 2.09, the Borrower shall
                    --------
pay, or shall cause to be paid, without duplication, interest on (i) the unpaid
principal amount of each Advance from and including the date of such Advance
(or, in the case of an Applied Provider Advance, from and including the date on
which the amount thereof was withdrawn from the Class B Cash Collateral Account
to pay interest on the Class B Certificates) to but excluding the date such
principal amount shall be paid in full (or, in the case of an Applied Provider
Advance, the date on which the Class B Cash Collateral Account is fully
replenished in respect of such Advance) and (ii) any other amount due hereunder
(whether fees, commissions, expenses or other amounts or to the extent permitted
by applicable law, installments of interest on Advances or any such other
amount) which is not paid when due (whether at stated maturity, by acceleration
or otherwise) from and including the due date thereof to but excluding the date
such amount is paid in full, in each such case, at a fluctuating interest rate
per annum for each day equal to the Applicable Liquidity Rate (as defined below)
for such Advance or such other amount as in effect for such day, but in no event
at a rate per annum greater than the maximum rate permitted by applicable law;
provided, however, that, if at any time the otherwise applicable interest rate
--------  -------
as set forth in this Section 3.07 shall exceed the maximum rate permitted by
applicable law, then any subsequent reduction in such interest rate shall not
reduce the rate of interest payable pursuant to this Section 3.07 below the
maximum rate permitted by applicable law until the total amount of interest
accrued equals the amount of interest that would have accrued if such otherwise
applicable interest rate as set forth in this Section 3.07 had at all times been
in effect.  Nothing contained in this Section 3.07 shall require the Borrower to
pay any amount under this Section 3.07 other than to the extent the Borrower
shall have funds available therefor.

               (b)  Except as provided in Section 3.07(e), each Advance shall be
either a Base Rate Advance or a LIBOR Advance as provided in this Section or
Section 3.10. Each such Advance shall be a Base Rate Advance for the period from
the date of its borrowing to (but excluding) the third Business Day following
the Liquidity Provider's receipt of the Notice of Borrowing for such Advance.
Thereafter, such Advance shall be a LIBOR Advance; provided, however, that the
                                                   --------  -------
Borrower (at the direction of the Controlling Party, so long as the Liquidity
Provider is not the Controlling Party) may (x) convert the Final Advance into a
Base Rate Advance on the last day of an Interest Period for such Advance by
giving the Liquidity Provider no less than four Business Days' prior written
notice of such election or (y) elect to maintain the

                                      15
<PAGE>

                                                    [Revolving Credit Agreement]


Final Advance as a Base Rate Advance by not requesting a conversion of the Final
Advance to a LIBOR Advance under Clause (5) of the applicable Notice of
Borrowing (or, if such Final Advance is deemed to have been made, without
delivery of a Notice of Borrowing pursuant to Section 2.06, by requesting, prior
to 11:00 A.M. (New York time) on the first Business Day following the Borrower's
receipt of the applicable Termination Notice, that such Final Advance not be
converted from a Base Rate Advance to a LIBOR Advance).

               (c)  Each LIBOR Advance shall bear interest during each Interest
Period at a rate per annum equal to LIBOR for such Interest Period plus the
Applicable Margin for such LIBOR Advance, payable in arrears on the last day of
such Interest Period and, in the event of the payment of principal of such LIBOR
Advance on a day other than such last day, on the date of such payment (to the
extent of interest accrued on the amount of principal repaid).

               (d)  Each Base Rate Advance shall bear interest at a rate per
annum equal to the Base Rate plus the Applicable Margin for such Base Rate
Advance, payable in arrears on each Regular Distribution Date and, in the event
of the payment of principal of such Base Rate Advance on a day other than a
Regular Distribution Date, on the date of such payment (to the extent of
interest accrued on the amount of principal repaid).

               (e)  Each Unapplied Provider Advance Shall bear interest in an
amount equal to the Investment Earnings on amounts on deposit in the Class B
Cash Collateral Account, payable in arrears on each Regular Distribution Date.

               (f)  Each amount not paid when due hereunder (whether fees,
     commissions, expenses or other amounts or, to the extent permitted by
     applicable law, installments of interest on Advances but excluding
     Advances) shall bear interest at a rate per annum equal to the Base Rate
     plus 2.0% per annum.

               (g)  Each change in the Base Rate shall become effective
immediately. The rates of interest specified in this Section 3.07 with respect
to any Advance or other amount shall be referred to as the "Applicable Liquidity
Rate."

     Section 3.08   Replacement of Borrower. Subject to Section 5.02, from time
                    -----------------------
to time and subject to the successor Borrower's meeting the eligibility
requirements set forth in Section 6.9 of the Intercreditor Agreement applicable
to the Subordination Agent, upon the effective date and time specified in a
written and completed Notice of Replacement Subordination Agent in substantially
the form of Annex VI (a "Notice of Replacement Subordination Agent") delivered
to the Liquidity Provider by the then Borrower, the successor Borrower
designated therein shall be substituted for as the Borrower for all purposes
hereunder.

     Section 3.09   Funding Loss Indemnification.  The Borrower shall pay to the
                    ----------------------------
Liquidity Provider, upon the request of the Liquidity Provider, such amount or
amounts as shall be sufficient (in the reasonable opinion of the Liquidity
Provider) to compensate it for any loss, cost, or expense incurred by reason of
the liquidation or redeployment of deposits or other funds acquired by the
Liquidity Provider to fund or maintain any LIBOR Advance (but excluding loss of
anticipated profits) incurred as a result of:

                                      16
<PAGE>

                                                    [Revolving Credit Agreement]

               (1)  Any repayment of a LIBOR Advance on a date other than the
last day of the Interest Period for such Advance; or

               (2)  Any failure by the Borrower to borrow a LIBOR Advance on the
date for borrowing specified in the relevant notice under Section 2.02.

     Section 3.10   Illegality.  Notwithstanding any other provision in this
                    ----------
Agreement, if any change in any applicable law, rule or regulation, or any
change in the interpretation or administration thereof by any governmental
authority, central bank or comparable agency charged with the interpretation or
administration thereof, or compliance by the Liquidity Provider (or its Lending
Office) with any request or directive (whether or not having the force of law)
of any such authority, central bank or comparable agency shall make it unlawful
or impossible for the Liquidity Provider (or its Lending Office) to maintain or
fund its LIBOR Advances, then upon notice to the Borrower by the Liquidity
Provider, the outstanding principal amount of the LIBOR Advances shall be
converted to Base Rate Advances (a) immediately upon demand of the Liquidity
Provider, if such change or compliance with such request, in the judgment of the
Liquidity Provider, requires immediate repayment; or (b) at the expiration of
the last Interest Period to expire before the effective date of any such change
or request.

                                  ARTICLE IV

                             CONDITIONS PRECEDENT

     Section 4.01   Conditions Precedent to Effectiveness of Section 2.01.
                    -----------------------------------------------------
Section 2.01 of this Agreement shall become effective on and as of the first
date (the "Effective Date") on which the following conditions precedent have
been satisfied or waived:

               (a)  The Liquidity Provider shall have received on or before the
Closing Date each of the following, each dated such date, and in the case of
each document delivered pursuant to paragraphs (i), (ii) and (iii), in form and
substance satisfactory to the Liquidity Provider:

                    (i)   This Agreement duly executed on behalf of the
     Borrower;

                    (ii)  The Intercreditor Agreement duly executed on behalf of
     each of the parties thereto (other than the Liquidity Provider);

                    (iii) Fully executed copies of each of the Operative
     Agreements (other than this Agreement and the Intercreditor Agreement);

                    (iv)  A copy of the Prospectus Supplement and specimen
     copies of the Class B Certificates;

                    (v)   An executed copy of each opinion, document, instrument
     and certificate delivered pursuant to the Class B Trust Agreement, the
     Intercreditor Agreement, the Note Purchase Agreement and the other
     Operative Agreements (together with, in the case of each such opinion,
     other than the opinion of counsel for the Underwriters, either addressed to
     the Liquidity Provider or accompanied by a letter from

                                      17
<PAGE>

                                                   [Revolving Credit Agreement]

     the counsel rendering such opinion to the effect that the Liquidity
     Provider is entitled to rely on such opinion as of its date as if it were
     addressed to the Liquidity Provider);

               (vi)  Evidence that there shall have been made and shall be in
     full force and effect, all filings, recordings and/or registrations, and
     there shall have been given or taken any notice or other similar action as
     may be reasonably necessary or, to the extent reasonably requested by the
     Liquidity Provider, reasonably advisable, in order to establish, perfect,
     protect and preserve the right, title and interest, remedies, powers,
     privileges, liens and security interests of, or for the benefit of, the
     Trustee and the Liquidity Provider created by the Operative Agreements; and

               (vii) Such other documents, instruments, opinions and approvals
     as the Liquidity Provider shall have reasonably requested.

          (b)  The following statements shall be true on and as of the Effective
Date:

               (i)   The representations and warranties in the Note Purchase
     Agreement and each of the Participation Agreements are true and correct on
     and as of the Effective Date as though made on and as of the Effective
     Date;

               (ii)  No event has occurred and is continuing, or would result
     from the entering into of this Agreement or the making of any Advance,
     which constitutes a Liquidity Event of Default; and

               (iii) The statements of financial position of United as of
     December 31, 2000 and June 30, 2001 and the related statements of earnings
     and cash flow of United for the year and six months then ended, fairly
     present the financial condition of United as at such dates and the results
     of operations and cash flow of United for the periods ended on such dates,
     in accordance with generally accepted accounting principles consistently
     applied (except as may be stated in the notes thereto), and subject in the
     case of the June 30, 2001 statements, to normal year-end audit adjustments,
     and since June 30, 2001, there has been no material adverse change in such
     condition or operations, except for such matters timely disclosed in press
     releases issued by UAL Corporation or United or in public filings,
     effective as of the date hereof, with the Securities and Exchange
     Commission under the Securities Exchange Act of 1934, as amended, by UAL
     Corporation or United .

          (c)  The Liquidity Provider shall have received payment in full of all
fees and other sums required to be paid to or for the account of the Liquidity
Provider on or prior to the Effective Date.

          (d)  All conditions precedent to the issuance of the Certificates
under the Trust Agreements shall have been satisfied or waived, all conditions
precedent to the effectiveness of the other Liquidity Facilities shall have been
satisfied or waived, and all conditions precedent to the purchase of the
Certificates by the Underwriters under the Underwriting Agreement shall have
been satisfied (unless any of such conditions precedent shall have been waived
by the Underwriters).

                                      18
<PAGE>

                                                   [Revolving Credit Agreement]

               (e)  The Borrower shall have received a certificate, dated the
date hereof, signed by a duly authorized representative of the Liquidity
Provider, certifying that all conditions precedent to the effectiveness of
Section 2.01 have been satisfied or waived.

     Section 4.02   Conditions Precedent to Borrowing.  The obligation of the
                    ---------------------------------
Liquidity Provider to make an Advance on the occasion of each Borrowing shall be
subject to the conditions precedent that the Effective Date shall have occurred
and, prior to the date of such Borrowing, the Borrower shall have delivered a
Notice of Borrowing which conforms to the terms and conditions of this Agreement
and has been completed as may be required by the relevant form of the Notice of
Borrowing for the type of Advances requested.

                                   ARTICLE V

                                   COVENANTS

     Section 5.01   Affirmative Covenants of the Borrower. So long as any
                    -------------------------------------
Advance shall remain unpaid or the Liquidity Provider shall have any Maximum
Commitment hereunder or the Borrower shall have any obligation to pay any amount
to the Liquidity Provider hereunder, the Borrower shall, unless the Liquidity
Provider shall otherwise consent in writing:

               (a)  Performance of Agreements. Punctually pay or cause to be
                    -------------------------
paid all amounts payable by it under this Agreement and the other Operative
Agreements and observe and perform in all material respects the conditions,
covenants and requirements applicable to it contained in this Agreement and the
other Operative Agreements.

               (b)  Reporting Requirements. Furnish to the Liquidity Provider
                    ----------------------
with reasonable promptness, such other information and data with respect to the
transactions contemplated by the Operative Agreements as from time to time may
be reasonably requested by the Liquidity Provider; and permit the Liquidity
Provider, upon reasonable notice, to inspect the Borrower's books and records
with respect to such transactions and to meet with officers and employees of the
Borrower to discuss such transactions.

               (c)  Certain Operative Agreements. Furnish to the Liquidity
                    ----------------------------
Provider with reasonable promptness any Operative Agreement entered into after
the date hereof.

     Section 5.02   Negative Covenants of the Borrower. So long as any Advance
                    ----------------------------------
shall remain unpaid or the Liquidity Provider shall have any Maximum Commitment
hereunder or the Borrower shall have any obligation to pay any amount to the
Liquidity Provider hereunder, the Borrower shall not appoint or permit or suffer
to be appointed any successor Borrower without the written consent of the
Liquidity Provider, which consent shall not be unreasonably withheld or delayed.

                                  ARTICLE VI

                          LIQUIDITY EVENTS OF DEFAULT

     Section 6.01   Liquidity Events of Default. If (a) any Liquidity Event of
                    ---------------------------
Default has occurred and is continuing and (b) there is a Performing Equipment
Note Deficiency, the

                                      19
<PAGE>

                                                   [Revolving Credit Agreement]

Liquidity Provider may, in its discretion, deliver to the Borrower a Termination
Notice, the effect of which shall be to cause (i) the obligation of the
Liquidity Provider to make Advances hereunder to expire on the fifth Business
Day after the date on which such Termination Notice is received by the Borrower,
(ii) the Borrower to promptly request, and the Liquidity Provider to promptly
make, a Final Advance in accordance with Section 2.02(d) and Section 3.6(i) of
the Intercreditor Agreement, (iii) all other outstanding Advances to be
automatically converted into Final Advances for purposes of determining the
Applicable Liquidity Rate for interest payable thereon, and (iv) subject to
Sections 2.07 and 2.09, all Advances (including, without limitation, any
Provider Advance and Applied Provider Advance), any accrued interest thereon and
any other amounts outstanding hereunder to become immediately due and payable to
the Liquidity Provider.

                                  ARTICLE VII

                                 MISCELLANEOUS

     Section 7.01   Amendments, Etc. No amendment or waiver of any provision of
                    ---------------
this Agreement, nor consent to any departure by the Borrower therefrom, shall in
any event be effective unless the same shall be in writing and signed by the
Liquidity Provider, and, in the case of an amendment, the Borrower, and then
such waiver or consent shall be effective only in the specific instance and for
the specific purpose for which given.

     Section 7.02   Notices, Etc. Except as otherwise expressly provided herein,
                    ------------
all notices and other communications provided for hereunder shall be in writing
(including sent by telecopier):

     Borrower:             State Street Bank and Trust Company of Connecticut,
                           National Association
                           225 Asylum Street
                           Goodwin Square
                           Hartford, Connecticut  06103
                           Attention:  Corporate Trust Division

                           Telephone:  860-244-1844
                           Telecopy:  860-244-1881

     Liquidity Provider:   Westdeutsche Landesbank Girozentrale,
                           New York
                           1211 Avenue of the Americas
                           New York, New York  10036


                           Business/Credit Contact
                           Attention:  Transportation Finance
                           Global Structured Finance/Americas
                           Telephone:  212-852-6115
                           Telecopy:  212-869-7634

                                      20
<PAGE>

                                                   [Revolving Credit Agreement]

                    Operations Contact
                    Attention:  Philip Green, Loan Administration
                    Telephone:  212-852-6113
                    Telecopy:  212-302-7946

or, as to each of the foregoing, at such other address as shall be designated by
such Person in a Written Notice to the others.  All such notices and
communications shall be effective (i) if given by telecopier, when transmitted
to the telecopier number specified above with receipt confirmed, (ii) if given
by mail, when deposited in the mails addressed as specified above, and (iii) if
given by other means, when delivered at the address specified above, except that
Written Notices to the Liquidity Provider pursuant to the provisions of Articles
II and III shall not be effective until received by the Liquidity Provider,
subject to the last sentence of Section 2.02(e).  A copy of all notices
delivered hereunder to either party shall in addition be delivered to each of
the parties to the Participation Agreements at their respective addresses set
forth therein.

     Section 7.03   No Waiver; Remedies. No failure on the part of the Liquidity
                    -------------------
Provider to exercise, and no delay in exercising, any right under this Agreement
shall operate as a waiver thereof; nor shall any single or partial exercise of
any right under this Agreement preclude any other or further exercise thereof or
the exercise of any other right. The remedies herein provided are cumulative and
not exclusive of any remedies provided by law.

     Section 7.04   Further Assurances. The Borrower agrees to do such further
                    ------------------
acts and things and to execute and deliver to the Liquidity Provider such
additional assignments, agreements, powers and instruments as the Liquidity
Provider may reasonably require or deem advisable to carry into effect the
purposes of this Agreement and the other Operative Agreements or to better
assure and confirm unto the Liquidity Provider its rights, powers and remedies
hereunder and under the other Operative Agreements.

     Section 7.05   Indemnification; Survival of Certain Provisions. The
                    -----------------------------------------------
Liquidity Provider shall be indemnified hereunder to the extent and in the
manner described in Section 5(b) of any Participation Agreement. In addition,
the Borrower agrees to indemnify, protect, defend and hold harmless the
Liquidity Provider from, against and in respect of, and shall pay on demand, all
Expenses (including the expenses set forth in Section 7 of the Note Purchase
Agreement) of any kind or nature whatsoever (other than any Expenses of the
nature described in Section 3.01, 3.02 or 7.07 hereof or in the Fee Letter
(regardless of whether indemnified against pursuant to said Sections or in such
Fee Letter)) that may be imposed, incurred by or asserted against any Liquidity
Indemnitee, in any way relating to, resulting from, or arising out of or in
connection with any action, suit or proceeding by any third party against such
Liquidity Indemnitee and relating to this Agreement, the Intercreditor
Agreement, the Fee Letter or any Participation Agreement; provided, however,
                                                          --------  -------
that the Borrower shall not be required to indemnify, protect, defend and hold
harmless any Liquidity Indemnitee in respect of any Expense of such Liquidity
Indemnitee to the extent such Expense is (i) attributable to the gross
negligence or willful misconduct of such Liquidity Indemnitee or any other
Liquidity Indemnitee, (ii) ordinary and usual operating overhead expense or
(iii) attributable to the failure by such Liquidity Indemnitee or any other
Liquidity Indemnitee to perform or observe any agreement, covenant or condition
on its part to be performed or observed in this Agreement, the Intercreditor
Agreement, the Fee Letter or any other Operative Agreement to which it is a
party. The indemnities and cost

                                      21
<PAGE>

                                                   [Revolving Credit Agreement]

provisions contained in Section 4(j) of the Note Purchase Agreement and Section
5(b) of any Participation Agreement and the provisions of Sections 3.01, 3.02,
3.03, 3.09 7.05 and 7.07 shall survive the termination of this Agreement.

     Section 7.06   Liability of the Liquidity Provider. (a) Neither the
                    -----------------------------------
Liquidity Provider nor any of its officers, directors, employees or affiliates
shall be liable or responsible for: (i) the use which may be made of the
Advances or any acts or omissions of the Borrower or any beneficiary or
transferee in connection therewith; (ii) the validity, sufficiency or
genuineness of documents, or of any endorsement thereon, even if such documents
should prove to be in any or all respects invalid, insufficient, fraudulent or
forged; or (iii) the making of Advances by the Liquidity Provider against
delivery of a Notice of Borrowing and other documents which do not comply with
the terms hereof; provided, however, that the Borrower shall have a claim
                  --------  -------
against the Liquidity Provider, and the Liquidity Provider shall be liable to
the Borrower, to the extent of any damages suffered by the Borrower which were
the result of (A) the Liquidity Provider's willful misconduct or negligence in
determining whether documents presented hereunder comply with the terms hereof,
or (B) any breach by the Liquidity Provider of any of the terms of this
Agreement, including, but not limited to, the Liquidity Provider's failure to
make lawful payment hereunder after the delivery to it by the Borrower of a
Notice of Borrowing complying with the terms and conditions hereof.

               (b)  Neither the Liquidity Provider nor any of its officers,
employees, directors or Affiliates shall be liable or responsible in any respect
for (i) any error, omission, interruption or delay in transmission, dispatch or
delivery of any message or advice, however transmitted, in connection with this
Agreement or any Notice of Borrowing delivered hereunder, or (ii) any action,
inaction or omission which may be taken by it in good faith, absent willful
misconduct or negligence (in which event the extent of the Liquidity Provider's
potential liability to the Borrower shall be limited as set forth in the
preceding paragraph), in connection with this Agreement or any Notice of
Borrowing.

     Section 7.07   Costs, Expenses and Taxes. The Borrower agrees to pay, or
                    -------------------------
cause to be paid (A) on the Effective Date and on such later date or dates on
which the Liquidity Provider shall make demand, all reasonable out-of-pocket
costs and expenses of the Liquidity Provider in connection with the preparation,
negotiation, execution, delivery, filing and recording of this Agreement, any
other Operative Agreement and any other documents which may be delivered in
connection with this Agreement, including, without limitation, the reasonable
fees and expenses of outside counsel for the Liquidity Provider and (B) on
demand, all reasonable costs and expenses of the Liquidity Provider (including
reasonable counsel fees and expenses) in connection with (i) the enforcement of
this Agreement or any other Operative Agreement, (ii) the modification or
amendment of, or supplement to, this Agreement or any other Operative Agreement
or such other documents which may be delivered in connection herewith or
therewith (whether or not the same shall become effective) or (iii) any action
or proceeding relating to any order, injunction, or other process or decree
restraining or seeking to restrain the Liquidity Provider from paying any amount
under this Agreement, the Intercreditor Agreement or any other Operative
Agreement or otherwise affecting the application of funds in the Class B Cash
Collateral Account. In addition, the Borrower shall pay any and all recording,
stamp and other similar taxes and fees payable or determined to be payable in
connection with the execution, delivery, filing and recording of this Agreement
any other Operative Agreement and such other

                                      22
<PAGE>

                                                   [Revolving Credit Agreement]

documents, and agrees to save the Liquidity Provider harmless from and against
any and all liabilities with respect to or resulting from any delay in paying or
omission to pay such taxes or fees.

     Section 7.08   Binding Effect; Participations. (a) This Agreement shall be
                    ------------------------------
binding upon and inure to the benefit of the Borrower and the Liquidity Provider
and their respective successors and assigns, except that neither the Liquidity
Provider (except as otherwise provided in this Section 7.08) nor the Borrower
(except as contemplated by Section 3.08) shall have the right to assign its
rights or obligations hereunder or any interest herein without the prior written
consent of the other party, subject to the requirements of Section 7.08(b). The
Liquidity Provider may grant participations herein or in any of its rights
hereunder and under the other Operative Agreements to such Persons (other than
United or any of its Affiliates) as the Liquidity Provider may in its sole
discretion select, subject to the requirements of Section 7.08(b). No such
participation by the Liquidity Provider, however, shall relieve the Liquidity
Provider of its obligations hereunder. In connection with any participation or
any proposed participation, the Liquidity Provider may disclose to the
participant or the proposed participant any information that the Borrower is
required to deliver or to disclose to the Liquidity Provider pursuant to this
Agreement. The Borrower acknowledges and agrees that the Liquidity Provider's
source of funds may derive in part from its participants. Accordingly,
references in this Agreement and the other Operative Agreements to
determinations, reserve and capital adequacy requirements, increased costs,
reduced receipts and the like as they pertain to the Liquidity Provider shall be
deemed also to include those of each of its participants that are banks
(subject, in each case, to the maximum amount that would have been incurred by
or attributable to the Liquidity Provider directly if the Liquidity Provider,
rather than the participant, had held the interest participated other than a
result of a change in law following the date of any participation).

               (b)  If, pursuant to Section 7.08(a) above, the Liquidity
Provider sells any participation in this Agreement to any bank or other entity
(each, a "Participating Institution"), then, concurrently with the effectiveness
of such participation, the Participating Institution shall (i) represent to the
Liquidity Provider (for the benefit of the Liquidity Provider and the Borrower)
either (A) that it is incorporated under the laws of the United States or a
state thereof or (B) that under applicable law and treaties, no taxes shall be
required to be withheld by the Borrower or the Liquidity Provider with respect
to any payments to be made to such Participating Institution in respect of this
Agreement, (ii) furnish to the Liquidity Provider and the Borrower either (x) a
statement that it is incorporated under the laws of the United States or a state
thereof or (y) if it is not so incorporated, two copies of a properly completed
United States Internal Revenue Service Form W-8ECI or Form W-8BEN, as
appropriate, or other applicable form, certificate or document prescribed by the
Internal Revenue Service certifying, in each case, such Participating
Institution's entitlement to a complete exemption from United States federal
withholding tax in respect to any and all payments to be made hereunder, and
(iii) agree (for the benefit of the Liquidity Provider and the Borrower) to
provide the Liquidity Provider and the Borrower a new Form W-8ECI or Form W-
8BEN, as appropriate, (A) on or before the date that any such form expires or
becomes obsolete or (B) after the occurrence of any event requiring a change in
the most recent form previously delivered by it and prior to the immediately
following due date of any payment by the Borrower hereunder, certifying in the
case of a Form W-8BEN or Form W-8ECI that such Participating Institution is
entitled to a complete exemption from United States federal withholding tax on
payments under this Agreement. Unless the Borrower

                                      23
<PAGE>

                                                   [Revolving Credit Agreement]

has received forms or other documents reasonably satisfactory to it (and
required by applicable law) from the Participating Institution indicating that
payments hereunder are not subject to United States federal withholding tax, the
Borrower shall withhold taxes as required by law from such payments at the
applicable statutory rate without any obligation to make additional payments
under Section 3.03.

               (c)  Notwithstanding the other provisions of this Section 7.08,
the Liquidity Provider may assign and pledge all or any portion of the Advances
owing to it to any Federal Reserve Bank or the United States Treasury as
collateral security pursuant to Regulation A of the Board of Governors of the
Federal Reserve System and any Operating Circular issued by such Federal Reserve
Bank, provided that any payment in respect of such assigned Advances made by the
Borrower to the Liquidity Provider in accordance with the terms of this
Agreement shall satisfy the Borrower's obligations hereunder in respect of such
assigned Advance to the extent of such payment. No such assignment shall release
the Liquidity Provider from its obligations hereunder.

     Section 7.09   Severability. Any provision of this Agreement which is
                    ------------
prohibited, unenforceable or not authorized in any jurisdiction shall, as to
such jurisdiction, be ineffective to the extent of such prohibition,
unenforceability or non-authorization without invalidating the remaining
provisions hereof or affecting the validity, enforceability or legality of such
provision in any other jurisdiction.

     Section 7.10   GOVERNING LAW. 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.

     Section 7.11   Submission to Jurisdiction; Waiver of Jury Trial; Waiver of
                    -----------------------------------------------------------
Immunity.
--------

               (a)  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 Operative
     Agreement, 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;

                    (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

                                      24
<PAGE>

                                                   [Revolving Credit Agreement]

     similar form of mail), postage prepaid, to each party hereto at its address
     set forth in Section 7.02, or at such other address of which the Liquidity
     Provider 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.

               (b)  THE BORROWER AND THE LIQUIDITY PROVIDER EACH HEREBY AGREE TO
WAIVE THEIR 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, without limitation, contract claims, tort claims,
breach of duty claims and all other common law and statutory claims. The
Borrower and the Liquidity Provider each warrant and represent 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.

               (c)  The Liquidity Provider hereby waives any immunity it may
have from the jurisdiction of the courts of the United States or of any State
and waives any immunity any of its properties located in the United States may
have from attachment or execution upon a judgment entered by any such court
under the United States Foreign Sovereign Immunities Act of 1976 or any similar
successor legislation.

     Section 7.12   Execution in Counterparts. This Agreement may be executed in
                    -------------------------
any number of counterparts and by different parties hereto on separate
counterparts, each of which counterpart, when so executed and delivered, shall
be deemed to be an original and all of which counterparts, taken together, shall
constitute but one and the same Agreement.

     Section 7.13   Entirety.  This Agreement and the other Operative Agreements
                    --------
constitute the entire agreement of the parties hereto with respect to the
subject matter hereof and supersedes all prior understandings and agreements of
such parties.

     Section 7.14   Headings. Section headings in this Agreement are included
                    --------
herein for convenience of reference only and shall not constitute a part of this
Agreement for any other purpose.

     Section 7.15   LIQUIDITY PROVIDER'S OBLIGATION TO MAKE ADVANCES.  EXCEPT AS
                    ------------------------------------------------
EXPRESSLY SET FORTH IN THIS AGREEMENT, THE OBLIGATIONS OF THE LIQUIDITY PROVIDER
TO MAKE ADVANCES HEREUNDER, AND THE BORROWER'S RIGHTS TO DELIVER NOTICES OF
BORROWING REQUESTING THE MAKING OF ADVANCES HEREUNDER, SHALL BE UNCONDITIONAL
AND IRREVOCABLE, AND SHALL BE PAID OR PERFORMED, IN EACH CASE STRICTLY IN

                                      25
<PAGE>

                                                   [Revolving Credit Agreement]

ACCORDANCE WITH THE TERMS OF THIS AGREEMENT AND SHALL CONSTITUTE THE OBLIGATIONS
OF WESTDEUTSCHE LANDESBANK GIROZENTRALE.

                                      26
<PAGE>

                                                   [Revolving Credit Agreement]

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed and delivered by their respective officers thereunto duly
authorized as of the date first set forth above.


                                             STREET BANK AND TRUST COMPANY OF
                                             CONNECTICUT, NATIONAL ASSOCIATION,
                                             not in its individual capacity but
                                             solely as Subordination Agent and
                                             Trustee, as Borrower


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

                                             WESTDEUTSCHE LANDESBANK
                                             GIROZENTRALE, ACTING THROUGH ITS
                                             NEW YORK BRANCH, as Liquidity
                                             Provider


                                             By: /s/ Brigitte Thieme
                                                --------------------------------
                                                 Name: Brigitte Thieme
                                                 Title: Managing Director

                                             By: /s/ Alfred Heynen
                                                --------------------------------
                                                 Name: Alfred Heynen
                                                 Title: Associate Director

                                      27
<PAGE>

                                                    [Revolving Credit Agreement]

                                                                      Annex I to
                                                      Revolving Credit Agreement

                     INTEREST ADVANCE NOTICE OF BORROWING

     The undersigned, a duly authorized signatory of the undersigned borrower
(the "Borrower"), hereby certifies to Westdeutsche Landesbank Girozentrale,
acting through its New York branch (the "Liquidity Provider"), with reference to
the Revolving Credit Agreement, dated as of August 22, 2001, between the
Borrower and the Liquidity Provider (the "Liquidity Agreement"; the terms
defined therein and not otherwise defined herein being used herein as therein
defined or referenced), that:

          (1)  The Borrower is the Subordination Agent under the Intercreditor
     Agreement.

          (2)  The Borrower is delivering this Notice of Borrowing for the
     making of an Interest Advance by the Liquidity Provider to be used for the
     payment of interest on the Class B Certificates which was payable on
     _____________________ in accordance with the terms and provisions of the
     Class B Trust Agreement and the Class B Certificates, which Advance is
     requested to be made on _______________. The Interest Advance should be
     transferred to account __________.

          (3)  The amount of the Interest Advance requested hereby (i) is
     $__________, to be applied in respect of the payment of interest which was
     due and payable on the Class B Certificates on such Distribution Date, (ii)
     does not include any amount with respect to the payment of principal of, or
     Additional Payments on, the Class A-1 Certificates, the Class A-2
     Certificates, the Class A-3 Certificates, the Class B Certificates, the
     Class C Certificates or the Class D Certificates, or interest on the Class
     A-1 Certificates, the Class A-2 Certificates, the Class A-3 Certificates,
     the Class C Certificates or the Class D Certificates, (iii) was computed in
     accordance with the provisions of the Class B Certificates, the Class B
     Trust Agreement and the Intercreditor Agreement (a copy of which
     computation is attached hereto as Schedule I), (iv) does not exceed the
     Maximum Available Commitment on the date hereof, and (v) has not been and
     is not the subject of a prior or contemporaneous Notice of Borrowing.

          (4)  Upon receipt by or on behalf of the Borrower of the amount
     requested hereby, (a) the Borrower shall apply the same in accordance with
     the terms of Section 3.6(b) of the Intercreditor Agreement, (b) no portion
     of such amount shall be applied by the Borrower for any other purpose and
     (c) no portion of such amount until so applied shall be commingled with
     other funds held by the Borrower.

     The Borrower hereby acknowledges that, pursuant to the Liquidity Agreement,
the making of the Interest Advance as requested by this Notice of Borrowing
shall automatically reduce, subject to reinstatement in accordance with the
terms of the Liquidity Agreement, the Maximum Available Commitment by an amount
equal to the amount of the Interest Advance requested to be made hereby as set
forth in clause (i) of paragraph (3) of this Notice of

                                    Annex I
                                    Page 1
<PAGE>

                                                    [Revolving Credit Agreement]

Borrowing and such reduction shall automatically result in corresponding
reductions in the amounts available to be borrowed pursuant to a subsequent
Advance.

     IN WITNESS WHEREOF, the Borrower has executed and delivered this Notice of
Borrowing as of the ____ day of ______________, ____.

                                       STATE STREET BANK AND TRUST
                                       COMPANY OF CONNECTICUT,
                                       NATIONAL ASSOCIATION,
                                       not in its individual capacity but solely
                                       as Subordination Agent, as Borrower


                                       By:______________________________________
                                          Name:
                                          Title:


                                    Annex I
                                    Page 2
<PAGE>

                                                    [Revolving Credit Agreement]

              SCHEDULE I TO INTEREST ADVANCE NOTICE OF BORROWING

  [Insert Copy of Computations in accordance with Interest Advance Notice of
                                  Borrowing]

                                    Annex I
                                    Page 3
<PAGE>

                                                    [Revolving Credit Agreement]

                                                                     Annex II to
                                                      Revolving Credit Agreement

                   NON-EXTENSION ADVANCE NOTICE OF BORROWING

     The undersigned, a duly authorized signatory of the undersigned borrower
(the "Borrower"), hereby certifies to Westdeutsche Landesbank Girozentrale,
acting through its New York branch (the "Liquidity Provider"), with reference to
the Revolving Credit Agreement, dated as of August 22, 2001, between the
Borrower and the Liquidity Provider (the "Liquidity Agreement"; the terms
defined therein and not otherwise defined herein being used herein as therein
defined or referenced), that:

          (1)  The Borrower is the Subordination Agent under the Intercreditor
     Agreement.

          (2)  The Borrower is delivering this Notice of Borrowing for the
     making of the Non-Extension Advance by the Liquidity Provider to be used
     for the funding of the Class B Cash Collateral Account in accordance with
     Section 3.6(d) of the Intercreditor Agreement, which Advance is requested
     to be made on __________, ____. The Non-Extension Advance should be
     transferred to ____________.

          (3)  The amount of the Non-Extension Advance requested hereby (i) is
     $_______________.__, which equals the Maximum Available Commitment on the
     date hereof and is to be applied in respect of the funding of the Class B
     Cash Collateral Account in accordance with Section 3.6(d) of the
     Intercreditor Agreement, (ii) does not include any amount with respect to
     the payment of the principal of, or Additional Payments on, the Class A-1
     Certificates, the Class A-2 Certificates, the Class A-3 Certificates, the
     Class B Certificates, the Class C Certificates or the Class D Certificates,
     or interest on the Class A-1 Certificates, the Class A-2 Certificates, the
     Class A-3 Certificates, the Class C Certificates or the Class D
     Certificates, (iii) was computed in accordance with the provisions of the
     Class B Certificates, the Class B Trust Agreement and the Intercreditor
     Agreement (a copy of which computation is attached hereto as Schedule I),
     and (iv) has not been and is not the subject of a prior or contemporaneous
     Notice of Borrowing under the Liquidity Agreement.

          (4)  Upon receipt by or on behalf of the Borrower of the amount
     requested hereby, (a) the Borrower will deposit such amount in the Class B
     Cash Collateral Account and apply the same in accordance with the terms of
     Section 3.6(d) of the Intercreditor Agreement, (b) no portion of such
     amount shall be applied by the Borrower for any other purpose and (c) no
     portion of such amount until so applied shall be commingled with other
     funds held by the Borrower.

     The Borrower hereby acknowledges that, pursuant to the Liquidity Agreement,
(A) the making of the Non-Extension Advance as requested by this Notice of
Borrowing shall automatically and irrevocably terminate the obligation of the
Liquidity Provider to make further Advances under the Liquidity Agreement; and
(B) following the making by the Liquidity

                                   Annex II
                                    Page 1
<PAGE>

                                                    [Revolving Credit Agreement]

Provider of the Non-Extension Advance requested by this Notice of Borrowing, the
Borrower shall not be entitled to request any further Advances under the
Liquidity Agreement. IN WITNESS WHEREOF, the Borrower has executed and delivered
this Notice of Borrowing as of the ____ day of _________, ____.

                                       STATE STREET BANK AND TRUST
                                       COMPANY OF CONNECTICUT,
                                       NATIONAL ASSOCIATION,
                                       not in its individual capacity but solely
                                       as Subordination Agent, as Borrower


                                       By:______________________________________
                                          Name:
                                          Title:

                                   Annex II
                                    Page 2
<PAGE>

                                                    [Revolving Credit Agreement]

                      SCHEDULE I TO NON-EXTENSION ADVANCE
                              NOTICE OF BORROWING
                [Insert copy of computations in accordance with
                  Non-Extension Advance Notice of Borrowing]

                                   Annex II
                                    Page 3
<PAGE>

                                                    [Revolving Credit Agreement]

                                                                    Annex III to
                                                      Revolving Credit Agreement

                     DOWNGRADE ADVANCE NOTICE OF BORROWING

     The undersigned, a duly authorized signatory of the undersigned borrower
(the "Borrower"), hereby certifies to Westdeutsche Landesbank Girozentrale,
acting through its New York branch (the "Liquidity Provider"), with reference to
the Revolving Credit Agreement dated as of August 22, 2001, between the Borrower
and the Liquidity Provider (the "Liquidity Agreement"; the terms defined therein
and not otherwise defined herein being used herein as therein defined or
referenced), that:

          (1)  The Borrower is the Subordination Agent under the Intercreditor
     Agreement.

          (2)  The Borrower is delivering this Notice of Borrowing for the
     making of the Downgrade Advance by the Liquidity Provider to be used for
     the funding of the Class B Cash Collateral Account in accordance with
     Section 3.6(c) of the Intercreditor Agreement by reason of the downgrading
     of the relevant rating of the Liquidity Provider issued by either Rating
     Agency below the Threshold Rating, which Advance is requested to be made on
     ______________. The Downgrade Advance should be transferred to __________.

          (3)  The amount of the Downgrade Advance requested hereby (i) is
     $________, which equals the Maximum Available Commitment on the date hereof
     and is to be applied in respect of the funding of the Class B Cash
     Collateral Account in accordance with Section 3.6(d) of the Intercreditor
     Agreement, (ii) does not include any amount with respect to the payment of
     principal of, or Additional Payments on, the Class A-1 Certificates, the
     Class A-2 Certificates, the Class A-3 Certificates, the Class B
     Certificates, the Class C Certificates or the Class D Certificates, or
     interest on the Class A-1 Certificates, the Class A-2 Certificates, the
     Class A-3 Certificates, the Class C Certificates or the Class D
     Certificates, (iii) was computed in accordance with the provisions of the
     Class B Certificates, the Class B Trust Agreement and the Intercreditor
     Agreement (a copy of which computation is attached hereto as Schedule 1),
     and (iv) has not been and is not the subject of a prior or contemporaneous
     Notice of Borrowing under the Liquidity Agreement.

          (4)  Upon receipt by or on behalf of the Borrower of the amount
     requested hereby, (a) the Borrower shall deposit such amount in the Class B
     Cash Collateral Account and apply the same in accordance with the terms of
     Section 3.6(d) of the Intercreditor Agreement, (b) no portion of such
     amount shall be applied by the Borrower for any other purpose and (c) no
     portion of such amount until so applied shall be commingled with other
     funds held by the Borrower.

     The Borrower hereby acknowledges that, pursuant to the Liquidity Agreement,
(A) the making of the Downgrade Advance as requested by this Notice of Borrowing
shall automatically and irrevocably terminate the obligation of the Liquidity
Provider to make further Advances

                                   Annex III
                                    Page 1
<PAGE>

                                                    [Revolving Credit Agreement]

under the Liquidity Agreement; and (B) following the making by the Liquidity
Provider of the Downgrade Advance requested by this Notice of Borrowing, the
Borrower shall not be entitled to request any further Advances under the
Liquidity Agreement.

     IN WITNESS WHEREOF, the Borrower has executed and delivered this Notice of
Borrowing as of the _____ day of _________, _____.

                                     STATE STREET BANK AND TRUST
                                     COMPANY CONNECTICUT,
                                     NATIONAL ASSOCIATION,
                                     not in its individual capacity but solely
                                     as Subordination Agent, as Borrower


                                     By:________________________________________
                                        Name:
                                        Title:

                                   Annex III
                                    Page 2
<PAGE>

                                                    [Revolving Credit Agreement]

              SCHEDULE I TO DOWNGRADE ADVANCE NOTICE OF BORROWING

                [Insert Copy of Computations in accordance with
                    Downgrade Advance Notice of Borrowing]

                                   Annex III
                                    Page 3
<PAGE>

                                                    [Revolving Credit Agreement]

                                                                     Annex IV to
                                                      Revolving Credit Agreement

                       FINAL ADVANCE NOTICE OF BORROWING

     The undersigned, a duly authorized signatory of the undersigned borrower
(the "Borrower"), hereby certifies to Westdeutsche Landesbank Girozentrale,
acting through its New York branch (the "Liquidity Provider"), with reference to
the Revolving Credit Agreement, dated as of August 22, 2001, between the
Borrower and the Liquidity Provider (the "Liquidity Agreement"); the terms
defined therein and not otherwise defined herein being used herein as therein
defined or referenced), that:

          (1)  The Borrower is the Subordination Agent under the Intercreditor
     Agreement.

          (2)  The Borrower is delivering this Notice of Borrowing for the
     making of the Final Advance by the Liquidity Provider to be used for the
     funding of the Class B Cash Collateral Account in accordance with Section
     3.6(i) of the Intercreditor Agreement by reason of the receipt by the
     Borrower of a Termination Notice from the Liquidity Provider with respect
     to the Liquidity Agreement, which Advance is requested to be made on
     _______________.

          (3)  The amount of the Final Advance requested hereby (i) is
     $____________, which equals the Maximum Available Commitment on the date
     hereof and is to be applied in respect of the funding of the Class B Cash
     Collateral Account in accordance with Section 3.6(i) of the Intercreditor
     Agreement, (ii) does not include any amount with respect to the payment of
     principal of, or Additional Payments on the Class A-1 Certificates, the
     Class A-2 Certificates, the Class A-3 Certificates, the Class B
     Certificates, the Class C Certificates, or the Class D Certificates, or
     interest on the Class A-1 Certificates, the Class A-2 Certificates, the
     Class A-3 Certificates, the Class C Certificates or the Class D
     Certificates, (iii) was computed in accordance with the provisions of the
     Class B Certificates, the Class B Trust Agreement and the Intercreditor
     Agreement (a copy of which computation is attached hereto as Schedule I),
     and (iv) has not been and is not the subject of a prior or contemporaneous
     Notice of Borrowing.

          (4)  Upon receipt by or on behalf of the Borrower of the amount
     requested hereby, (a) the Borrower shall deposit such amount in the Class B
     Cash Collateral Account and apply the same in accordance with the terms of
     Section 3.6(i) of the Intercreditor Agreement, (b) no portion of such
     amount shall be applied by the Borrower for any other purpose and (c) no
     portion of such amount until so applied shall be commingled with other
     funds held by the Borrower.

                                   Annex IV
                                    Page 1
<PAGE>

                                                    [Revolving Credit Agreement]

          (5)  The Borrower hereby requests that the Advance requested hereby be
     a Base Rate Advance [and that such Base Rate Advance be converted into a
     LIBOR Advance on the third Business Day following your receipt of this
     notice.]1

     The Borrower hereby acknowledges that, pursuant to the Liquidity Agreement,
(A) the making of the Final Advance as requested by this Notice of Borrowing
shall automatically and irrevocably terminate the obligation of the Liquidity
Provider to make further Advances under the Liquidity Agreement; and (B)
following the making by the Liquidity Provider of the Final Advance requested by
this Notice of Borrowing, the Borrower shall not be entitled to request any
further Advances under the Liquidity Agreement.

     IN WITNESS WHEREOF, the Borrower has executed and delivered this Notice of
Borrowing as of the _____ day of ___________, _____.

                                   STATE STREET BANK AND TRUST
                                   COMPANY OF CONNECTICUT,
                                   NATIONAL ASSOCIATION,
                                   not in its individual capacity but solely
                                   as Subordination Agent, as Borrower


                                   By:__________________________________
                                      Name:
                                      Title:












___________________
/1/  Bracketed language may be included at Borrower's option.

                                   Annex IV
                                    Page 2
<PAGE>

                                                    [Revolving Credit Agreement]

                SCHEDULE I TO FINAL ADVANCE NOTICE OF BORROWING

                [Insert Copy of Computations in accordance with
                      Final Advance Notice of Borrowing]

                                   Annex IV
                                    Page 3
<PAGE>

                                                    [Revolving Credit Agreement]


                                                                      Annex V to
                                                      Revolving Credit Agreement

                             NOTICE OF TERMINATION


                                    [Date]

State Street Bank and Trust Company
of Connecticut, National Association,
  as Subordination Agent, as Borrower
225 Asylum Street
Goodwin Square
Hartford, Connecticut  06103


Attention: Corporate Trust Administration

     Re:  Revolving Credit Agreement, dated as of August 22, 2001, between State
          Street Bank and Trust Company of Connecticut, National Association, as
          Subordination Agent, as agent and trustee for the United Airlines
          2001-1B Pass Through Trust, as Borrower, and Westdeutsche Landesbank
          Girozentrale, acting through its New York branch (the "Liquidity
          Agreement")

Ladies and Gentlemen:

     You are hereby notified that pursuant to Section 6.01 of the Liquidity
Agreement, by reason of the occurrence of a Liquidity Event of Default and a
Performing Equipment Note Deficiency (each as defined therein), we are giving
this notice to you in order to cause (i) our obligations to make Advances (as
defined therein) under such Liquidity Agreement to terminate on the fifth
Business Day after the date on which you receive this notice and (ii) you to
request a Final Advance under the Liquidity Agreement pursuant to Section 3.6(i)
of the Intercreditor Agreement (as defined in the Liquidity Agreement) as a
consequence of your receipt of this notice.

     THIS NOTICE IS THE "NOTICE OF TERMINATION" PROVIDED FOR UNDER THE LIQUIDITY
AGREEMENT.  OUR OBLIGATIONS TO MAKE ADVANCES UNDER THE LIQUIDITY AGREEMENT SHALL
TERMINATE ON THE FIFTH BUSINESS DAY AFTER THE DATE ON WHICH YOU RECEIVE THIS
NOTICE.

                                    Annex V
                                    Page 1
<PAGE>

                                                    [Revolving Credit Agreement]


                                          Very truly yours,

                                          WESTDEUTSCHE LANDESBANK
                                          GIROZENTRALE, ACTING THROUGH
                                          ITS NEW YORK BRANCH,
                                          as Liquidity Provider


                                          By:______________________________
                                             Name:
                                             Title:


                                          By:______________________________
                                             Name:
                                             Title:


cc:  State Street Bank and Trust Company
     of Connecticut, National Association, as Trustee

                                    Annex V
                                    Page 2
<PAGE>

                                                    [Revolving Credit Agreement]

                                                                     Annex VI to
                                                      Revolving Credit Agreement

                   NOTICE OF REPLACEMENT SUBORDINATION AGENT


                                    [Date]

Attention:

     Re:  Revolving Credit Agreement, dated as of August 22, 2001, between State
          Street Bank and Trust Company of Connecticut, National Association, as
          Subordination Agent, as agent and trustee for the United Airlines
          2001-1B Pass Through Trust, as Borrower, and Westdeutsche Landesbank
          Girozentrale, acting through its New York branch (the "Liquidity
          Agreement")

Ladies and Gentlemen:

     For value received, the undersigned hereby irrevocably transfers to:

                        ______________________________
                        [Name of Transferee]

                        ______________________________
                        [Address of Transferee]

all rights and obligations of the undersigned as Borrower and Subordination
Agent under the Liquidity Agreement referred to above.  The transferee has
succeeded the undersigned as Borrower and Subordination Agent under the
Intercreditor Agreement referred to in the first paragraph of the Liquidity
Agreement, pursuant to the terms of Section 8.1 of the Intercreditor Agreement.

     By this transfer, all rights of the undersigned as Borrower and
Subordination Agent under the Liquidity Agreement are transferred to the
transferee and the transferee shall hereafter have the sole rights and
obligations as Borrower and Subordination Agent  thereunder.  The undersigned
shall pay any costs and expenses of such transfer, including, but not limited
to, transfer taxes or governmental charges.

                                   Annex VI
                                    Page 1
<PAGE>

                                                    [Revolving Credit Agreement]

     We ask that this transfer be effective as of ____________, ____.

                                   STATE STREET BANK AND TRUST COMPANY OF
                                   CONNECTICUT, NATIONAL ASSOCIATION,
                                   not in  its individual capacity but solely as
                                   Subordination Agent, as Borrower


                                   By:__________________________________
                                      Name:
                                      Title:

                                   Annex VI
                                    Page 2