When I started my collection (not knowing really that it would someday turn into a “collection”) as a kid in the ’70s, I always (always) built model planes with their landing gear up, because the primary use for the models was for “flying” against my buddies’ planes in our garden toy-soldier wars. To have our planes configured for sitting on the ground just didn’t compute.
That practice of building models that look like they are in the air actually continued until a handful of years ago, but as I have gotten more and more into staged photo shoots of dioramas it now makes more sense to have the landing gear down, so the planes can be realistically depicted in static scenes, like this one I put together earlier this month. I mean, they’re models; it’s hard for them to be shown realistically flying!
I have tried, though, and this set shows a few planes I chose for the purpose because they happen to have propellers that spin easily enough to be set in motion for a photo. Of course it’s a photographic illusion, but for the planes I have that never got their wheels, I think this method puts them in the best light I can hope to manage!