A Virgin flight from London to New York had to turn back after the co-pilot revealed he was still a trainee.
It was just 40 minutes into its transatlantic flight when the first officer radioed to tell his stunned captain that he hadn't completed his last flying test.
The New York-bound passengers were left furious when the plane turned around to land and they were stuck on the tarmac for almost three hours as airline staff tried to find an experienced replacement.
Virgin Atlantic apologised for Monday's blunder, which it said had been caused by a roster mistake.
A source told The Sun: "You could have cut the tension in the cockpit with a knife.