There are lots of solutions for this, and I hope I don't sound like a shill
for them, but the Metrix Mark II box with a $10 omni rubber duck antenna
inside the hangar and a $40 directional antenna on the other radio card will
do exactly what you need.
You could also do it with a Ubiquity Nano station outside the building aimed
at the FBO and any wireless router inside the hanger. Run the nano station
networking cable into the building, through the POE splitter and connect it
to the gateway jack on the router. Set up the Nano as the gateway and have
it connect itself to the FBO. You gotta run NAT on the Nano. I set one of
these up for my sister about 3000' from a free AP for less than $100.
Good luck!