For even more Stinson build options go to:
DGA Home Page -> Free Stuff -> dhc3007ski.pdf
This is a PDF with 1:48 optional winter skis for the DGA DHC-3 Otter, formatted for A4 paper - print at 2 pages per US letter sheet to get very close to 1:72 scale. I found a period photo of NC-15132 with skis mounted on main wheels but not the tail wheel.
For 1:72 diorama 2D figures go to:
juniorgeneral.org -> Paper Soldiers -> Early 20th
-> American Gangsters
-> Spanish Civil War
-> Others
juniorgeneral.org -> Paper Soldiers -> WW2
practically everything!
The pre-WW2 section even has 2 full marching bands and a bicycle band, the Spanish band in tan uniforms should be fine as-is. Gangsters and G-men would make a great airport getaway diorama.