They’re not free, but most are reasonably priced and I immediately picked up the J2F Grumman Duck and Sikorsky S-38 Flying Boat from their Between the Wars range for $5.95us each. The Junkers Ju-52 is also very tempting, but a little more pricey at $14.95us.
They accept PayPal and once you purchase the models, they immediately become available for download as a series of PDF files from your Fiddlers Green account pages, despite what the site says about PayPal payments taking some days to clear. For each model you get a regular and large version as well as several variations, one of which always seems to be a simple black and white version which you can edit yourself for a custom appearance.
I’m unsure if the scale is consistent between models, as the regular version of the Sikorsky Flying Boat is clearly marked as 1:46th scale while the Grumman Flying Duck doesn’t directly indicate scale. However each model includes at least one ‘figure’ in the form of a standing pilots and/or ground crew so you can scale the planes from them.
I’ve printed out a reduced version of the Sikorsky Flying Boat (1:46th at 82% = 1:56th scale) to keep it consistent with my other Pulp vehicles and am half-way through assembling it at the moment. It looks like an excellent toy for that American millionaire adventurer gadding about Africa with his hunting pals.