Here's a very simple 3D puzzle of an airplane, very loosely based on a Spitfire.

With this puzzle I tried something a bit different from my previous two 3D jigsaw puzzles, 2025 and a heart.  The connecting pieces are tapered, so that they are easier to insert, and arranged such that, provided you support the airplane in the middle, gravity will keep all the pieces in place.

My initial intention was to make this a puzzle for children, but (a) this version is a bit small at about 6 inches (150mm) wingspan, and (b) it comes to pieces easily if you attempt to lift it by anything other than the centre piece, due to the tapered interconnects.  Simply scaling it up likely wont work well as the clearance in the interconnects will scale as well, making the connections too loose.  Ideally I think it needs interconnects that are not tapered, and which have a sufficiently close fit that they don't just fall apart.  Probably the settings used for the heart would work.  That way children could play with it once assembled.  Ask in the comments if you are interested in something like that.

There are two print profiles available, one for larger build plates with an AMS, one for all build plates, no AMS required.

I print this with variable layer height and tree supports.  This works pretty well, but a lot of care is needed to remove the supports from the propeller.

I used Bambu PLA Basic.