I brought my 1938 600cc engine over to England with Norwegian Air Lines some 3 years ago for an overhaul by Roger. The crankcase with pistons and rods & all accessories packed into a light suicase weighed ca. 31 kilos. The cylinder block weighed 9 kilos, and I managed to convince the airport security to accept it as cabin luggage. It was thoroughly cleaned before departure to avoid oily smells.
The flywheel on a two-speeder is quite a bit heavier than the one on a later Flyer/Rep type engine because the periphery is one and a half inches wide, compared to one inch on the later engines, AND the hole in the middle is smaller. Two-speeder crankcase is a bit lighter though. IMHO they should have stayed with the heavier flywheel…..
I mixed up two airplane-trips with Scott engines. The trip in 2009, which has been described in detail in Yowl vol.26: No.8, February 2010, page 255ff was actually made with a complete engine, well packed with lots of old towels and bubble wrapping.
The complete engine with packing material weighed 31.5 kilos. Maximum weight allowed by Norwegian for check-in luggage was 32 kilos. I would imagine that your engine weighs more or less the same.