An AEF Chipmunk landing on the old 26 at Edinburgh was hit by a golf ball once
Nasty, very nasty. In particular, what do the local rules say about this? Do you have to take a drop and lose a stroke, or play it as a lost ball? Or do you head off to the airport, wait till the aircraft lands, and then play it from where it was embedded in the air intake? If it was an outbound transatlantic flight, the water hazard across the course is quite something...