@Matushka
If you mean what controls what aircraft spawn at the airport/zancudo & sometimes flying around the map etc, it's 'vehiclemodelsets.meta':
...\Grand Theft Auto V\mods\update\update.rpf\common\data\ai\vehiclemodelsets.meta
Example:
<Item type="CAmbientModelSet">
<Name>AIRPORT_PLANES</Name>
<Models>
<Item>
<Name>jet</Name>
<Variations type="NULL" />
<Probability value="1.000000" />
</Item>
</Models>
</Item>
<Item type="CAmbientModelSet">
<Name>AIRPORT_PLANES_SMALL</Name>
<Models>
<Item>
<Name>luxor</Name>
<Variations type="NULL" />
<Probability value="1.000000" />
</Item>
<Item>
<Name>shamal</Name>
<Variations type="NULL" />
<Probability value="1.000000" />
</Item>
</Models>
</Item>
...
<Item type="CAmbientModelSet">
<Name>ARMY_HELI</Name>
<Models>
<Item>
<Name>cargobob</Name>
<Variations type="NULL" />
<Probability value="1.000000" />
</Item>
</Models>
</Item>
...
<Item type="CAmbientModelSet">
<Name>jet</Name>
<Models>
<Item>
<Name>LAZER</Name>
<Variations type="NULL" />
<Probability value="1.000000" />
</Item>
</Models>
</Item>
'vehiclemodelsets.meta' is pretty flexible. You don't need to stick to what is there, you can add in new vehicles to sections & the game will randomly choose which one to spawn etc. They are spawned using scenarios, so it's even possible to create completely new locations & specifics of how something spawns if required etc.
Note:
At some point, if you add tons of new vehicles to 'vehiclemodelsets.meta' the game will go crazy & start swapping vehicles about. You'll see stuff like the game trying to take-off in SUV's on the airport runway & such. You just lower the number of vehicles in there to fix it.
Also seen errors in 'vehiclemodelsets.meta' edits that corrupt 'update.rpf'. So backup the complete 'update.rpf' before editing
