I found some free downloadable PDFs here - http://www.toy-plane.co.uk/airfield-buildings - one of which was a control tower, I printed out a couple of them and made up the following, improvising the hand rail with cardboard and a spare piece of plastic ladder.
For the hangars, I made up something similar to the Bellman Hangar. They have a foamboard shell with cardboard roof, cardboard doors and runners. I modelled one with a door part open.
All of these will be painted up and used in story line posts with other suitable buildings and accessories; either on this blog for a german airfield or a british one on Somewhere in England.