jabrams72

It's only certain of the taxes and you only don't pay them on the portion of the ticket for which the voucher is paying--although it also is dependent upon the voucher being coded correctly.

As of 2004, quoted from Flyertalk somewhere (I have it saved on my desktop):
I recently received very exact information from a very helpful AA employee and am sharing it here.

It concerns exactly how to go about getting a ticket which is purchased w/a Voluntary Denied Boarding Voucher without paying domestic taxes.

I hope you find it helpful. Here it is in its entirety:

N*VOUCHER Lines 12-26
12N MOST TRANSPORTATION VOUCHERS ARE TAX EXEMPT.
THIS IS
13N DETERMINED BY THE TICKET DESIGNATOR. THE
FOLLOWING
14N TICKET DESIGNATORS ARE TAX EXEMPT-
15N .
16N DV-DENIED BOARDING/VOLUNTARY
17N DI-DENIED BOARDING/INVOL
18N BC-BAGGAGE CLAIMS
19N BD-BAG DELIVERY
20N DB-DAMAGED BAG
21N CE-CONSEQUENTIAL EXP
22N IT-INTERRUPTED TRIP
23N DG-DOWNGRADE
24N PS-PASSENGER SERVICE
25N CC-COMSUMER CLAIMS
26N CI-CONSUMER INTERRUPTED TRIP

N*TVOUCHERS Lines 60-117
Tax Exempt Vouchers (back to top)
--------------------------------------------------------------------------------
When the voucher amount is equal to or greater than
the base fare of the ticket, US1/US2 do not apply and
when no US tax is collected, ZP and AY will not apply.
All other taxes and fees do apply.
When the voucher amount is Less than the base fare of
the ticket: If the US1 applies, it is calculated on
the fare amount not covered by the voucher. If there is
as little as $0.01 base fare not covered by the
voucher, then US1 will be calculated on that amount. US2
will be collected in full if any base fare amount is not
covered by the voucher. If any amount of US1 is
collected, ZP applies. If any amount of US1 is collected, AY
applies.


F*RFPKTR
TKT ------------------- TICKET - VOUCHER
----------------------
TRANSPORTATION VOUCHER TAXES
RFPKTR
---------------------------------------------------------------
DESCRIPTION
------------
US, ZP, AY TAX DETAILS/RULES
POLICY
-------
AMOUNTS OF TRANSPORTATION VOUCHERS OTHER THAN THE
VOUCHERS APPLIED TO A TICKET ARE EXEMPT FROM US TAX.
US TAX-EXEMPT TRANSPORTATION VOUCHER CODES-
DI, DV, BC, BD, CE, DB, DG, DV, IT, PS, CC, CI
ONLY THE US, AY AND ZP TAXES/FEES WOULD EVER BE
AFFECTED BY USE OF A US TAX-EXEMPT VOUCHER.
WHEN THE VOUCHER TOTAL IS LESS THAN THE BASE
FARE, ALL TAXES AND FEES APPLY, EXCEPT THAT US1
7.5 PCT TAX WOULD BE CHARGED ONLY ON THE FARE
DIFFERENCE, WHEN APPLICABLE TO THE ROUTING. US2,
ZP AND AY APPLY IN FULL.
SINCE SABRE AIR PRICING FUNCTIONS /WP AND T-REX
PRICE-P ACTION/ WILL PROVIDE ALL TAXES, FEES AND
CHARGES APPLICABLE TO THE ROUTING AND FARE,
AGENTS MUST MAKE ADJUSTMENTS IN THE T-REX TAX
SCREENS.