Woodsy,
Here's a few shots showing how I did the hangar background for my air field diorama board.
I took photos of several different types of hangars while attending air shows at Nellis AFB (I'm only showing one here though).
Any distractions - like modern era halogen lights - were Photoshopped out, the photos printed on heavy cardstock, then mounted to foamcore.
I attached a flap at the back with about 2" sticking below the bottom of the foamcore which allowed me to insert the photo between the back of the diorama base and the larger backdrop.
This prevents the photo from just flopping over as well as allowing me to place it anywhere I like. So far, it's worked pretty good.
The in-progress photos were taken on my older 20" x 8ft shelf runway where I used Woodland Scenics 'Top Coat - Concrete' as the color for my ramp (the area in front of the hangars).
It is more of a tan color but did the job for me at the time. You'll notice however that the photo of the actual hangar shows a more realistic light gray forward of the doors, and this is how the new board is painted.
From Vegas Air Field
Ed