There were 14,903 flight diversions by U.S. airlines in the 12-month period ending in June, according to an Associated Press analysis of Department of Transportation reports. That means, 41 flights a day, on average, make unscheduled landings at other airports.
The government doesn't break out the reason for diversions, but industry experts say the vast majority occur because of bad weather or mechanical problems. And diversions remain a tiny portion of the 6 million annual flights in the U.S. — less than a quarter of a percentage point.
The decision to divert is up to the pilot. Delta spokesman Morgan Durrant says the crew must determine if the person is going to cause harm to others or has terrorist intentions.