It doesn’t count for the tank you are using.
Aircraft do not unlock new modifications nor new tanks.
Aircraft only gain RP that benefit aircraft, at least in GRB and GSB.
GAB is an ENTIRELY DIFFERENT BEAST.
GRB/GSB have a strong overlap.
GSB is somewhat better than GRB due to lack of scouting markers and much higher skill floor for using aircraft, but with dedicated practice even in GSB you can end up with dominant untouchable quality using stuff like the Yak-9K, F4U-4/F4U-4B, F6F and their ilk - precision dive bombing is not that difficult if you got fine rudder control inputs and a big monitor with a strong graphics cards.
I am not capable of it, but I’ve seen a fair few people capable of planting bombs right next to tanks following real life dive bombing doctrine in bf109s and the like.
I used to think GSB is a safe haven from CAS due to the difficulty of flying aircraft, but that was just my projecting my own skill issues onto others.
And most importantly?
Even if planes added RP to the tank being used?
It doesn’t matter.
When I boot up GRB, or have the super rare chance to catch a GSB day where I have the lineup to play at WW2 tiers and in the mood to use that lineup…
I and doing so because I want to play tanks.
I want to drive around in a T-34, PzIV, Tiger, Panther, Sherman, wacky british engingeering and so on and so forth.
If I wanted to fly planes, do you know what I would do?
I’d click “Events - Air Simulator Battles” and join a match at a BR bracket that looks populated and fun.
Do you know why?
Because flying and dogfighting in GRB/GSB is bloody awful.
The map is TINY. There’s like a 8 x 8 km bowl that is flanked by airfields on each end.
If you try and use hit and run/boom and zoom tactics, there’s a significant chance that during your unloaded extension into a shallow climb (no more than ~6-8 m/s to maintain speed) you’ll get hit by hitscan magic anti-aircraft fire and are forced to turn around.
If you dive on enemy aircraft, there’s a chance that by the time you are within effective gun range (200-500 meters), you’re being hit by magic hitscan AAA fire.
And on top of this all,
in GRB you have planes phasing into reality out of thin air.
And on top of this all,
You might be mid dogfight that’s a lot of fun, setting up for position or energy advantage and suddenly…
Thanks to ticket bleed or the awfully short match duration even in GSB - the dogfight gets interrupted by the match ending.
Given that a dogfight initiated at equal energy and with a sufficiently skilled opponent to threaten you in turn can easily last a good minute if not more… 25 minutes of match timer is awfully short for any kind of fun air to air combat in my opinion.
I have a clip of Bf109G14 vs 2 F6F-5(n) (presumably in voice chat - they were quite decently coordinated!) that alone took 5 minutes of methodical back and forth ambushes in the clouds until one side finally won. (much longer if you consider the set-up and jockeying before the first time an attack run was attempted)
Another clip of Yak1B vs Bf109F4 has us fighting for 2:30 minutes following neutral head-on exchange descending from 3.5km altitude down to barely skimming the surface of old stalingrad with our bellies.
Neither of those engagements could have happened in GRB or GSB.