<PAGE>

                                                                    EXHIBIT 10.8
 
                             WHITTAKER CORPORATION
                          SUPPLEMENTAL BENEFITS PLAN
                          --------------------------

     This Supplemental Benefit Plan (hereinafter referred to as the "Plan") has
been adopted by the Board of Directors of Whittaker Corporation, a Delaware
corporation (hereinafter referred to as the "Company"), effective as of January
1, 1988.

     1. Purpose
        -------

        The purpose of the Plan is to provide supplemental retirement income for
certain Employees who participate in the Whittaker Corporation Employees'
Pension Plan whose retirement benefits are reduced because of the maximum
limitation on annual compensation under Code Section 401(a)(17).

     2. Definitions
        -----------

        The following definitions, set forth in alphabetical order, are used
throughout the Plan. Terms or phrases appearing in capital letters that are not
defined below shall have the same meanings as under the Retirement Plan, as
defined below.

        (a) "Board of Directors" means the Board of Directors of the Company.

        (b) "Code" means the Internal Revenue Code of 1986, as amended and in
effect from time to time.

        (c) "Committee" means the Compensation and Stock Option Committee of the
Board of Directors.

        (d) "Participant" means an executive officer of Whittaker Corporation
who satisfies the conditions for eligibility described in Section 3. The term
"Participant" shall also include the Beneficiary of a deceased Participant.

        (e) "Retirement Plan" means the Whittaker Corporation Employees' Pension
Plan, as amended from time to time, which is a defined benefit pension plan
qualified under Section 401(a) of the Code.

        (f) "Supplemental Benefit" means the benefit described in Section 4.

     3. Eligibility to Participate
        --------------------------

        Each Participant whose aggregate pension benefit under the Retirement
Plan and any other defined benefit pension

                                      -1-
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of an Affiliated Company is reduced by reason of the maximum limitation on
annual compensation under Code Section 401(a)(17).

     4. Supplemental Benefits
        ---------------------

        (a) Amount of Benefits
            ------------------

            Each Participant shall be entitled to a Supplemental Benefit under
this Plan in an amount equal to the actuarial equivalent of (i) - [(ii) +
(iii)], where:

            (i) equals the aggregate amount of monthly pension benefit payable
to the Participant under the Retirement Plan and any other defined benefit
pension plan of an Affiliated Company on the normal benefit commencement date
specified in the Retirement Plan and such other defined benefit pension plan, as
determined under the normal retirement benefit formula of the Retirement Plan
and such other defined benefit pension plan before applying any provision of the
Plan that would reduce benefits because of the maximum benefit limitations under
Code Section 415 or the maximum dollar limitation on annual compensation under
Code Section 401(a)(17);

           (ii) equals the aggregate amount of a Participant's monthly pension
benefit determined in paragraph (i) above after applying the maximum benefit
limitations under Code Section 415 and the maximum dollar limitation on annual
compensation under Code Section 401(a)(17); and

          (iii) equals the aggregate amount of the monthly pension benefit
payable to the Participant pursuant to the terms of the Whittaker Corporation
Excess Benefit Plan, as amended from time to time thereafter.

        (b) Form of Benefits
            ----------------

            The Supplemental Benefit determined in subsection (a) above shall be
paid to the Participant in the form of a monthly, straight-life annuity. The
amount of such annuity shall be determined by the actuary for the Retirement
Plan using the actuarial assumptions set forth in the Retirement Plan for
purposes of determining the actuarial equivalent of alternative forms of
benefits.

     5. Vesting
        -------

        Subject to the rights of general creditors as set forth in Section 7 and
the right of the Company to discontinue the Plan as provided in Section 10, a
Participant shall have a vested and nonforfeitable interest in the Supplemental
Benefit

                                      -2-
<PAGE>
 
to the same extent and in the same manner as the Participant's benefits become
vested under the Retirement Plan.

     6. Commencement of Benefits
        ------------------------

        The Supplemental Benefit under this Plan shall commence on the later of:
(a) the date on which the Participant is first eligible to begin receiving a
benefit under the Retirement Plan; or (b) the first day of the month next
following the date of the Participant's Severance from the Company.

     7. Funding of Benefits
        ------------------- 

        (a) The Plan shall be unfunded and each Participant shall have the
status of a general unsecured creditor with respect to the Company's obligation
to make payments under this Plan. All benefits payable under the Plan shall be
paid from the Company's general assets, and nothing contained in the Plan shall
require the Company to set aside or hold in trust any funds for the benefit of a
Participant. Any funds of the Company available to pay benefits under the Plan
shall be subject to the claims of general creditors of the Company and may be
used for any purpose by the Company.

        (b) Notwithstanding the provisions of subsection (a), the Company may,
at the direction, and in the absolute discretion, of the Board of Directors,
transfer to the trustee of one or more trusts established for the benefit of one
or more Participants assets from which all or a portion of the benefits provided
under the Plan will be satisfied, provided that such assets held in trust shall
at all times be subject to the claims of general unsecured creditors of the
Company, and no Participant shall at any time have a prior claim to such assets.

     8. Administration of the Plan
        --------------------------

        The Committee shall administer the Plan. The Committee shall keep a
written record of its action and proceedings regarding the Plan and all dates,
records and documents relating to its administration of the Plan. The Committee
is authorized to interpret the Plan, to make, amend and rescind such rules as it
deems necessary for the proper administration of the Plan, to make all other
determinations necessary or advisable for the administration of the Plan and to
correct any defect or supply any omission or reconcile any inconsistency in the
Plan in the manner and to the extent that the Committee deems desirable to carry
the Plan into effect. The powers and duties of the Committee shall include,
without limitation, the following:

                                      -3-
<PAGE>
 
        (a) Resolving all questions relating to the eligibility Of an Employee
to become a Participant;

        (b) Determining the amount of benefits payable to Participants and
authorizing and directing the Company with respect to the payment of benefits
under the Plan;

        (c) Construing and interpreting the Plan whenever necessary to carry out
its intention and purpose and making and publishing such rules for the
regulation of the Plan as are not inconsistent with the terms of the Plan; and

        (d) Compiling and maintaining all records it determines to be necessary,
appropriate or convenient in connection with the administration of the Plan.

        Any action taken or determination made by the Committee shall, except as
otherwise provided in Section 11 below, be conclusive on all parties. No member
of the Committee shall vote on any matter relating specifically to such member.
In the event that a majority of the members of the Committee will be
specifically affected by any action proposed to be taken (as opposed to being
affected in the same manner as each other Participant in the Plan), such action
shall be taken by the Board of Directors.

        Notwithstanding the foregoing, the Committee may delegate to one or more
persons or entities any or all of the responsibilities, duties or powers of the
Committee under this Plan.

     9. Claims Procedure
        ----------------

        (a) If a Participant (hereinafter referred to as the "Claimant") does
not receive the timely payment of the benefits which the Claimant believes are
due under the Plan, the Claimant may make a claim for benefits in the manner
hereinafter provided.

            All claims for benefits under the Plan shall be made in writing and
shall be signed by the Claimant. Claims shall be submitted to a representative
designated by the Committee and hereinafter referred to as the "Claims
Coordinator." If the Claimant does not furnish sufficient information with the
claim for the Claims Coordinator to determine the validity of the claim, the
Claims Coordinator shall indicate to the Claimant any additional information
which is necessary for the Claims Coordinator to determine the validity of the
claim.

                                      -4-
<PAGE>
 
            Each claim hereunder shall be acted on and approved or disapproved
by the Claims Coordinator within 90 days following the receipt by the Claims
Coordinator of the information necessary to process the claim.

            In the event the Claims Coordinator denies a claim for benefits in
whole or in part, the Claims Coordinator shall notify the Claimant in writing of
the denial of the claim and notify the Claimant of his or her right to a review
of the Claims Coordinator's decision by the Committee. Such notice by the Claims
Coordinator shall also set forth, in a manner calculated to be understood by the
Claimant, the specific reason for such denial, the specific provisions of the
Plan on which the denial is based, a description of any additional material or
information necessary to perfect the claim with an explanation of the Plan's
appeals procedure as set forth in this Section.

            If no action is taken by the Claims Coordinator on an Claimant's
claim within 90 days after receipt by the Claims Coordinator, such claim shall
be deemed to be denied for purposes of the following appeals procedure.

        (b) Any Claimant whose claim for benefits is denied in whole or in part
may appeal for a review of the decision by the Committee. Such appeal must be
made within three months after the Claimant has received actual or constructive
notice of the denial as provided above. An appeal must be submitted in writing
within such period and must:

            (i) request a review by the Committee of the claim for benefits
under the Plan;

           (ii) set forth all of the grounds upon which the Claimant's request
for review is based and any facts in support thereof; and

          (iii) set forth any issues or comments which the Claimant deems
pertinent to the appeal.

          The Committee shall regularly review appeals by Claimants. The
Committee shall act upon each appeal within 60 days after receipt thereof unless
special circumstances require an extension of the time for processing, in which
case a decision shall be rendered by the Committee as soon as possible but not
later than 120 days after the appeal is received by the Committee.

          The Committee shall make a full and fair review of each appeal and any
written materials submitted by the Claimant in connection therewith. The
Committee may

                                      -5-
<PAGE>
 
require the Claimant to submit such additional facts, documents or other
evidence as the Committee in its discretion deems necessary or advisable in
making its review. The Claimant shall be given the opportunity to review
pertinent documents or materials upon submission of a written request to the
Committee, provided the Committee finds the requested documents or materials are
pertinent to the appeal.

          On the basis of its review, the Committee shall make an independent
determination of the Claimant's eligibility for benefits under the Plan. The
decision of the Committee on any claim for benefits shall be final and
conclusive upon all parties thereto.

          In the event the Committee denies an appeal in whole or in part, the
Committee shall give written notice of the decision to the Claimant, which
notice shall set forth, in a manner calculated to be understood by the Claimant,
the specific reasons for such denial and which shall make specific reference to
the pertinent provisions of the Plan on which the Committee's decision is based.

     10. Miscellaneous
         -------------

         (a) Nothing in the Plan shall confer upon a Participant the right to
continue in the employ of the Company or an Affiliated Company or shall limit or
restrict the right of the Company or any Affiliated Company to terminate the
employment of a Participant at any time with or without cause.

         (b) Except as otherwise provided in the Plan, no right or benefit under
the Plan shall be subject to anticipation, alienation, sale, assignment, pledge,
encumbrance or charge, and any attempt to anticipate, alienate, sell, assign,
pledge, encumber or charge such right or benefit shall be void. No such right or
benefit shall in any manner be liable for or subject to the debts, liabilities
or torts of a Participant. In addition, none of the rights of a Participant are
transferable by inter vivos gift or testamentary disposition.

         (c) The Plan may be amended at any time by the Committee provided such
amendment does not have the effect of increasing, directly or indirectly, the
benefit of any Participant. The Plan may also be amended or terminated by the
Board of Directors at any time, and any amendment adopted by the Board of
Directors shall supersede any prior or later amendment adopted by the Committee
that is inconsistent with the action of the Board of Directors. No amendment
shall have the effect of decreasing a Participant's accrued benefit.

                                      -6-
<PAGE>
 
         (d) The Plan is intended to provide benefits for "management or highly
compensated" employees within the meaning of Sections 201, 301 and 401 of ERISA,
and therefore to be exempt from the provisions of Parts 2, 3 and 4 of Title I of
ERISA. Accordingly, except for Supplemental Benefits in pay status, in the event
it is determined by a court of competent jurisdiction or by an opinion of
counsel based on judicial decisions or administrative pronouncements of the
Department of Labor that the Plan constitutes an employee pension benefit plan
within the meaning of Section 3(2) of ERISA, which is not so exempt, in the sole
discretion of the Board of Directors either (i) the Plan shall thereafter be
modified and operated and administered in such a manner as to comply with the
provisions of Parts 2, 3 and 4 of Title I of ERISA or (ii) the Plan shall
terminate and no further benefits shall accrue hereunder. If the Plan is
terminated, the benefit of each Participant accrued under the Plan on the date
of termination shall be paid immediately to such Participant in a single lump
sum payment.

         (e) If any benefit payment hereunder becomes payable to a Participant
determined by the Committee to be under any legal incapacity, payments under
this Plan shall be made to the guardian or legal representative of such person
and such payment shall constitute a full and complete discharge of all
obligations under this Plan to the Participant.

         (f) If multiple claims are received by the Committee with respect to
any benefits payable under this Plan, payment by the Committee to such person or
persons as the Committee determines to be entitled to receive such payment shall
constitute a full and complete discharge of all obligations with respect to such
payment. Benefit payment under this Plan may be suspended by the Committee
pending resolution to the satisfaction of the Committee of multiple claims.

         (g) If any provision in the Plan is held by a court of competent
jurisdiction to be invalid, void or unenforceable, the remaining provisions
shall nevertheless continue in full force and effect without being impaired or
invalidated in any way.

         (h) The Plan shall be construed and governed in all respects in
accordance with applicable federal law and, to the extent not preempted by such
federal law, in accordance with the law of the State of California.

                                      -7-
<PAGE>
 
         Executed at Los Angeles, California this 23rd day of November, 1988.
                                                  ----        --------

                                         WHITTAKER CORPORATION

                                         By: /s/ ^^??^^
                                            ----------------------
                                             Its:  VP
                                                 -----------------

                                      -8-
<PAGE>
 
the beginning thereof.

     WHEREAS the Board of Directors of this corporation (the "Board") previously
adopted the Whittaker Corporation Supplemental Benefit Plan (the "Plan"); and

     WHEREAS Section 10(c) of the Plan provides that the Board may amend the
Plan at any time, and the Board has determined that it is now necessary and
appropriate to amend the Plan as hereinafter set forth.

     NOW, THEREFORE, BE IT RESOLVED that Section 2 of the Plan is hereby amended
by adding the following new paragraphs at the end thereof:

          "(g) `Day of Service' means, in the case of any Employee, each day
during any period commencing with the day on which the Employee first enters
into active service as an Employee on or following his most recent date of
rehire by the Company or any Affiliated Company and ending on the date of his
next following Severance. If an Employee's Severance date is the date of his
retirement, discharge or voluntary termination of employment, then Day of
Service shall also include each day between such Severance date and the date
upon which the Employee recommences active service as an Employee if the
Employee recommences such active service Prior to:

               (1) The first anniversary of such Severance date if such
Severance date did not occur during an absence from service by the Employee for
a reason other than retirement, discharge or voluntary termination of
employment; or

                                       4
<PAGE>
 
               (2) The first anniversary of the date on which the Employee was
first absent from service for a reason other than retirement, discharge or
voluntary termination of employment if such Severance date occurred during such
absence.

               Credit for Days of Service shall be given with respect to periods
of military service to such extent and for such purposes as are required by
applicable federal law. Credit for Days of Service shall be given with respect
to service performed for an operating unit, division or subsidiary of any
corporation, trade or business that is acquired by the Company or any Affiliated
Company commencing on the effective date of such acquisition. Notwithstanding
the provisions of paragraph (1), the Board of Directors or the Committee by
resolution may provide that, for purposes of determining Vested Service, credit
for Days of Service also shall be given with respect to service performed for
such an entity prior to the effective date of the acquisition. Finally, Days of
Service shall include any period of service that constitutes service with a
predecessor employer within the meaning of Section 414(a)(1) of the Code.

          (h) 'Early Retirement Age' means the date on which a Participant
attains age 55 and completes at least 10 years of Vested Service, as determined
for purposes of this Plan and the Retirement Plan.

          (i) 'Normal Retirement Age' means the date on which a Participant
attains age 65. Notwithstanding the foregoing, effective with respect to
Participants who are hired after attaining age 60 and after December 31, 1988,
Normal Retirement Age means the fifth anniversary of the date on which such a
Participant becomes a Participant in the Plan.

          (j) 'Severance' means a Participant's termination of employment with
the Company and all Affiliated Companies for any reason at any time.

          (k) 'Vested Service' means the number of years of an Employee's Vested
Service determined according to this subsection. An Employee shall be deemed to
accrue a full year of Vested Service for each calendar year during which he
completes at least 365 Days of Service as an Employee. In addition, an Employee
shall be deemed to accrue a fractional year of Vested Service in any calendar
year in which he

                                       5
<PAGE>
 
     completes one or more but less than 365 Days of Service as an Employee.
     Such fractional year of Vested Service shall be computed by dividing the
     number of Days of Service completed by the Employee during such calendar
     year by 365."

     RESOLVED FURTHER that Section 5 of the Plan is hereby amended in its
entirety to read as follows:

          "5. Reduction of Excess Benefits
              ----------------------------

          Notwithstanding any provision of the Plan to the contrary, the
Supplemental Benefit of each Participant who has a Severance prior to the date
on which he attains Normal Retirement Age and is not again an Employee on such
date shall be proportionately reduced in accordance with the following schedule:

Participant's Years                                    Reduction
of Vested Service                                      Percentage
-------------------                                    ----------
Less than 5                                               100%
At least 5                                                  0%"

          RESOLVED FURTHER that Section 6 of the Plan is hereby amended in its
entirety to read as follows:

          "6. Commencement of Benefits

          The Supplemental Benefit under this Plan shall commence on the first
     day of the month next following the later of: (a) the date on which the
     Participant has a Severance; (b) in the case of a Participant who completes
     at least 10 years of Vested Service prior to his Severance, the date on
     which the Participant attains Early Retirement Age; or (c) in the case of a
     Participant who does not complete at least 10 years of Vested Service prior
     to his Severance, the date on which the Participant attains Normal
     Retirement Age."

     RESOLVED FURTHER that the last two paragraphs of Section 8 of the Plan are
hereby amended to read as follows:

          "Notwithstanding the foregoing, the Committee may delegate to one or
more persons or entities any or all of the responsibilities, duties or powers of
the Committee under this Plan. Any action taken or determination made by the
Committee or its delegatees shall, except as otherwise provided in

                                       6
<PAGE>
 
     Section 10, be conclusive as to all parties. Neither a member of the
     Committee nor a delegatee may vote on, or take any action with respect to,
     any matter relating to such member or delegatee. If a delegatee cannot take
     any action with respect to a matter, such action shall be taken by the
     Committee. Similarly, if a majority of the members of the Committee cannot
     take any action with respect to a matter, such action shall be taken by the
     Board of Directors."

     RESOLVED FURTHER that the first sentence of Section 10(b) of the Plan is
hereby amended by deleting the phrase "Except as otherwise provided in the
Plan," from the beginning thereof.

     RESOLVED FURTHER that Section 10(c) of the Plan is hereby amended by adding
the following two sentences at the end thereof:

     "If the Plan is terminated, no additional Supplemental Benefits shall
     accrue after the termination date. Any Supplemental Benefits that have
     already accrued as of the termination date shall be distributed at the time
     and in the manner specified in Section 4(b) and Section 6, above."

     RESOLVED FURTHER that Section 10(d) of the Plan is hereby amended in its
entirety to read as follows:

          "The Plan is intended to provide benefits for 'management or highly
     compensated employees' within the meaning of Sections 201, 301 and 401 of
     ERISA, and therefore to be exempt from the provisions of Parts 2, 3 and 4
     of Title I of ERISA. Accordingly, if a court of competent jurisdiction, the
     Department of Labor or the Internal Revenue Service, as the case may be,
     makes a final determination that the Plan constitutes an employee pension
     benefit plan within the meaning of Section 3(2) of ERISA, which is not so
     exempt, then in the sole discretion of the Board of Directors either (i)
     the Plan shall thereafter be modified and operated and administered in such
     a manner as to comply with the provisions of Parts 2, 3 and 4 of Title I of
     ERISA, or (ii) the Plan shall terminate and no further benefits shall
     accrue hereunder. If the Plan is so terminated, then, notwithstanding
     Section 10(c), the benefit accrued under the Plan as of the termination
     date by each Participant (including a Participant whose benefit is in pay
     status) shall be paid to such Participant in a single lump sum payment
     within 30
                                       7
<PAGE>
 
     days after the termination date."

     RESOLVED FURTHER that Section 10 of the Plan is hereby amended by moving
Section 10(f) to the end of Section 9 and redesignating Sections 10(g) and 10(h)
as Sections 10(f) and 10(g), respectively.

                                       8
<PAGE>
 
                           * * * * * * * * * * * * *

          I, Edward R. Muller, do hereby certify that I am the duly elected and
acting Secretary of Whittaker Corporation: that the foregoing is a full, true
and correct copy of the resolutions adopted at a meeting of the Board of
Directors of Whittaker Corporation held May 18, 1990, at which meeting a quorum
of said Board was at all times present and acting and that said resolutions have
not been modified or rescinded and are in full force and effect as of the date
of this certificate.

Date: June 12, 1990

                                         /s/ Edward R. Muller 
                                         ------------------------ 
                                             Edward R. Muller
                                                Secretary

                                      11
<PAGE>
 
                        CERTIFIED COPY OF RESOLUTIONS 
                         OF THE BOARD OF DIRECTORS OF 
                             WHITTAKER CORPORATION

          WHEREAS the Board of Directors of this corporation (the "Board")
     previously adopted the Whittaker Corporation Supplemental Benefit Plan (the
     "Plan"); and

          WHEREAS Section 10(c) of the Plan provides that the Board may amend
     the Plan at any time, and the Board has determined that it is now necessary
     and appropriate to amend the Plan as hereinafter set forth.

          NOW, THEREFORE, BE IT RESOLVED that Section 4(a)(i) of the Plan is
     hereby amended in its entirety to read as follows:

               "(i)   equals the aggregate amount of monthly pension benefit
          payable to the Participant under the Retirement Plan (without regard
          to the Third Amendment to such Plan) and any other defined benefit
          pension plan of an Affiliated Company on the normal benefit
          commencement date specified in the Retirement Plan and such other
          defined benefit pension plan, as determined under the normal
          retirement benefit formula of the Retirement Plan (without regard to
          the Third Amendment to such Plan) and such other defined benefit
          pension plan before applying any provisions of such plans that would
          reduce benefits because of the maximum benefit limitations under Code
          Section 415 or the maximum dollar limitation on annual compensation
          under Code Section 401(a)(17);".

                             * * * * * * * * * * *

     I, Nadine D. Leonsky, do hereby certify that I am a duly elected and acting
Assistant Secretary of Whittaker Corporation; that the foregoing is a full, true
and correct copy of resolutions adopted at a meeting of the Board of Directors
of Whittaker Corporation held November 9, 1990, at which meeting a quorum of
said Board was at all times present and acting and that said resolutions have
not been modified or rescinded and are in full force and effect as of the date
of this certificate.

     Date: July 12, 1991

                                                /s/ Nadine D. Leonsky
                                                ------------------------ 
                                                    Nadine D. Leonsky
                                                   Assistant Secretary