I do not know the hansa kits, but I believe that one is a control tower and the other a maintainence building.
If this is correct then they date from the late 1920s onward for the control tower and from 1900 for the maintainence building if in Europe.
There are lots of photographic references in black and white for the RAF airfield buildings in Britain; I don't know about the USAAF/USAF records. RAF bases in Asia, Northern India, the Middle East and Africa were quite different as they were built of local materials.
Try these links:
Also Google 'RAF airfield buildings' for more links.
Most RAF buildings constructed in the 1920s and 1930s were built of brick with tiled pitched roofs; control towers may also have been built of concrete or cinder blocks and then skimmed with a cement render. Generally the brick was brownish-red with some ares having a lighter red colour (brick colour depends upon clays and firing with variations across the country, depending upon where bricks were made). Window frames were often metal ('Crittall windows', worth a google) but may be wood, usually painted white. In 1938-39 many buildings were camouflaged with green, brown, dark grey or black paint. This was done in almost random curved patterns (see RAF aircraft camo upper surfaces for some ideas) using whatever paints were available. The finish was poor, faded quite quickly on some buildings but more slowly on others and wasn't always completed or even started on smaller structures. Hangars got priority.
Wartime buildings constructed in the UK were brick, cement or cinder block or wooden with tile, concrete slab, corrugated iron or wood and tar-paper roofs. Finish was often poor. Timber buildings were often painted with creosote, giving a dark brown colour. This applied to both the RAF and all other air forces based in the UK.
Hope this helps, maybe someone somewhere can hep you with the American structures outside of the UK.