A Virgin Atlantic co-pilot has been arrested at Heathrow Airport on suspicion of being over the legal alcohol limit, police have said.
Passengers were delayed for three-and-a-half hours
The 42-year-old first officer was held after police boarded the passenger jet on Sunday morning, as final checks were being carried out before take-off.
The 266 passengers on the Miami-bound flight were delayed while a replacement flight deck crew was found.
A spokesman for Scotland Yard said the man was later freed on bail.
"At 11.16am officers arrested a 42-year-old crew member on board a Virgin Atlantic flight to Miami. He was arrested under section 94 of the Railways and Transport Safety Act 2003," he said.
It is understood the arrested man was acting as relief first officer on the flight, providing cover for the captain and his co-pilot.
A spokeswoman for Virgin Atlantic said the crew member has been suspended from duty pending a police investigation.
She said: "Virgin Atlantic can confirm that one of its first officers has been released on police bail in connection with an allegation made this morning.
"Virgin Atlantic would like to apologise for the inconvenience caused and would like to reassure passengers that the airline will be investigating this matter thoroughly in accordance with its strict company policies in relation to operational staff.
"The safety and security of its passengers and crew is Virgin Atlantic's top priority."
Following the airline's policy, all members of the three-man flight deck were replaced following the arrest, causing the flight's delay.
Airline regulations recommend flight crews do not drink alcohol less than eight hours before flying.