The Docs have seen instances from pilots of all aircraft types and apparently long distance lorry drivers are particularly susceptible. It's the sensory constancy that does it. Busy brains need stimulus and when we don't get it we just start thinking too much
Hmm, I think I must have been close driving down the Keys then. Cruise control, open road, no traffic, and about 5 hours at 55 mph (the speed limit). Just miles and miles of the same - white concrete, blue skies. You certainly would not get that on the M1 or M25.