1. Open Editor
2. Create player (preferably explosion specialist)
3. Create aircraft (empty plane)
4. Set aircraft elevation higher than 1
5. Create Vehicle Respawn Module
6. Sync Respawn Module to the aircraft
7. Set Positsion "Starting Positsion"
8. Start Preview
9. Destroy the aircraft
10. New aircraft will spawn as flying and goes on its way

If this is indended then there should be option to set it as flying or none or what ever.

EDIT: Since BI doesn't care about bugs that won't get up voted, here is solution: Make vehicle spawn on the ground and then place a trigger under it and use setpos or setposASL command to insert it where ever you want it.