It occurred to me tonight that advances in materials science probably make it possible today to build a coal-fired steam- propulsion aircraft. Not a very practical aircraft, but one that could fly out of ground effect, and then land. People criticize Howard Hughes's record-setting aircraft for not getting above ground effect. Nobody ever mentions that it only flew in a straight line, so I'll assume that's okay. (It would probably be poor form to bail out and allow the aircraft to crash after setting the records, in lieu of landing.)
I'm thinking a small, high-performance motorcycle engine could be modified with a new camshaft to convert steam to mechanical energy. A titanium firetube boiler would be the lightest source of high-pressure steam. That would probably have to be custom-made, unless there's a community of high-performance steam enthusiasts of which I am unaware. An existing ultralight aircraft could be adapted to the new powerplant.
In one flight, a couple of dozen records could be set. Distance record for a coal-fueled aircraft. Distance record for a steam-propulsion aircraft. Altitude record for a coal-fueled aircraft (even if it was only 30 feet). Endurance record, speed record, number of passengers, wingspan, fuel efficiency per pound of coal, etc. I'd guess that a high-performance burner would need size-classified coal particles operated as a fluidized bed, probably with a screw conveyor to feed new fuel into the burner.