An airline cabin crew was suspended after claims that attendants drank alcohol during a flight.
The nine crew members were based at Gatwick Airport
First Choice Airways began an inquiry after a passenger reported the incident during a nine-hour flight from Cancun, Mexico, to Manchester.
The crew members, who are based at Gatwick Airport, were said to have drunk Bailey's cream liqueur aboard the plane carrying 300 holidaymakers.
Police were informed but said it was being dealt with by the airline.
The incident is said to have taken place on a flight, which left Mexico on Sunday evening and landed at 0646 GMT on Monday.
A female passenger, from Penrhyn Bay, in north Wales, said she saw staff pouring shots of alcohol into their coffee while working on flight FCA005.
She reported the matter to police when the aircraft landed at Manchester Airport.
The nine crew members returned to Gatwick Airport before they could be questioned by police.
A First Choice Airways spokeswoman said if the claims were proved the staff could be sacked.
"First Choice Airways is taking this allegation very seriously," she said.
"All our flight crew are trained that drinking is not acceptable from eight hours before operating a flight or during a flight.
"We immediately launched an investigation which is currently ongoing. The crew have been suspended pending the outcome of the internal investigation."
A Greater Manchester Police spokeswoman confirmed the matter had been reported to them but said it was being dealt with by the airline.