I for one would appreciate some period appropriate 1/48 autos, trucks and such. Late 30's and early 40's vehicles would add tremendous range and dimension to aircraft dioramas. Even moden vehicles would fill a void. Civilian or military - either way it would make things more interesting. I would love to build a scene of a bunch of pilots piled into a Jeep or a convertable scrambling to their awaiting aircraft. Not that it was all that good of a movie, but the visual image of that scene in 'Pearl Harbor' has stuck with me.
I am currently working on a scene involving an airshow pilot parking near his restored P-51D. I had to do it all in 1/24th scale because the choice of vehicles is wide open, but the choice of aircraft and figures is somewhat limited. The drawback is that working in such a large scale demands a level of detailing and scratchbuilding that is a stretch for me time wise and talent wise. If it were done in 1/48 scale, I think the project would be quite a bit easier to complete and display.