British Airways' flight BA223 has left Heathrow for Washington DC after being delayed for the fifth day running.
About 200 passengers endured the prolonged wait on Monday
The aircraft should have departed at 1505 GMT, but the 206 passengers on board had to wait until 1644.
The same flight was cancelled on 1 and 2 January and delayed by over three hours on each of the next three days.
Passengers had to wait one hour and 45 minutes before taking off Tuesday. The latest delay came as BA waited for clearance from US authorities.
The fifth postponement came after French authorities announced they were hunting an al-Qaeda suspect who had booked on an Air France flight to the US on Christmas
Eve but failed to turn up.
French Justice minister Dominique Perben said: "I confirm that we are looking for someone, but I can't say more.
"What's important when someone doesn't take a plane is to know why he didn't take it."
In London, British Airways and the Department of Transport refused to comment when asked if the disruption to BA transatlantic flights was connected to the French hunt for an Afghan who is on the US terrorism watch list.