[bell-cot]

Flight delays / cancellations / diversions (due to mechanical problems, weather, etc.) are a very regular thing - the airlines, ground crews, commercial pilots, and control towers have lots of experience with "Flight 1234 won't be taking off..." and "Flight 2345 is being diverted to...".

Or, if it's a "Bob owns a Cessna, and took off anyway" situation - well, Bob's license to fly a private airplane will probably be taken away. Maybe his Cessna, too. And (post-9/11) Bob could be spending some time in uncomfy little rooms with bars on the windows.

[gbil]

To add, my personal experience from the air force is that flight plan rejection from Eurocontrol was business-as-usual situation so I'm also confused reading that the system instead of rejecting that one problematic plan, threw a white-towel