Npc_create npc_enter npc here (in this case, probably gunship)
or to make in spawn in the air (the other way is really buggy)
No clip into the sky, where you want it, and type
give npc_gunship
then no clip away from the spot.
But, the ai is really dodgy for them. I believe that the gunships need air nodes to function properly, and people are still trying to figure out how to create those ingame.