1) Select “spawn” under the “Object” tab and place it.
2) Click "Goto" to zoom in.
3) In properties set “Object Type” to “Veh Entry”, in the “Object Properties” window
4) While selected, “Rotate”, any unassigned spawn direction is ok.
5) Now change the “Object Type” to “Ftr Entry”, in the “Object Properties” window again
6) Last thing, set Y to your air spawn alt.