Re: calling for backup
Yes, you can have a Summons and have the summoned creatures pay for the vehicle.
No, as a GM, the character with the summons could NOT use the copter, no matter how loyal the followers are; unless you are using the rules that the players do not have to pay for 'found' items.
Also, while this may seem like a great idea, as a GM, I would REQUIRE you to designate a point of origin (if they bought the copter). Unless the summons is magical (in which case you dont need the copter anyway), they have to fly the physical distance from origin to call location, which takes time.
Thanx for your time...
~J~