A Ryanair steward drank whiskey from the aircraft's drinks trolley and downed a small bottle of wine while he was working and the flight was in the air, a court has been told.
Sam Thompson, 26, was on duty when a witness saw him drink Jack Daniels from the trolley before taking a small bottle of wine from his pocket and "necking the whole bottle", Chelmsford Magistrates' Court heard.
On Monday, the defendant, of Warrenfield Close, Cheshunt, Hertfordshire, admitted to performing an aviation function as a member of cabin crew while his ability to do so was impaired by drink.
He is due to be sentenced at the same court on August 3 and was told he might be jailed.
Read more >>> Holidaymaker left with £400 bill after easyJet cancels flight to Southend at last minute
Nishma Khan, prosecuting, said police were called at around 6.10pm on May 18 this year after a witness reported seeing a member of cabin crew drinking while working on a flight.
She said the witness first saw Thompson drink Jack Daniels, before they "proceeded to film the member of staff".
"He was still on duty while the flight was in the air," she said.
Ms Khan said the witness saw Thompson sit down and "take a small bottle of wine out of his pocket and necking the whole bottle".
Police took a breath test from Thompson at Stansted Airport in Essex, with a reading of 50mcg of alcohol in 100ml of breath, before he gave a lower reading of 39mcg at Harlow police station.
Ms Khan said the legal limit is 9mcg of alcohol per 100ml of breath, which is lower than the legal limit for driving of 35mcg of alcohol per 100ml of breath.
Michael Carroll, for Thompson, said the defendant and alcohol are "not the best of friends".
Presiding magistrate, Kristien Chafer, ordered a pre-sentence report to be prepared on the defendant, exploring all sentencing options, including custody.
He bailed Thompson until his sentencing.