The three-hour tarmac limit applies only to U.S. airlines and to domestic flights. But DOT Secretary Ray LaHood indicated the U.K.-based airline could face penalties for possibly violating other rules.
USA Today
The pilot on a Virgin Atlantic flight that spent several hours on the tarmac after being diverted to Connecticut had asked for permission to let the passengers get off the plane, but a customs official threatened to have them arrested if they did, the airline said Thursday.
Washington Post
Damned if you do; damned if you don't.