Paul Grebenc, 35, was due to fly as first officer on a United Airlines flight from Glasgow Airport to Newark, New Jersey, on August 27 last year when concerns were raised about his fitness to fly.
A blood test carried out later that day found he had 42 milligrams of alcohol in 100 millilitres of blood, more than twice the legal limit of 20mcg.
Sheriff David Pender sentenced the former US Air Force pilot to 10 months behind bars after Grebenc pleaded guilty to the offence when he appeared at Paisley Sheriff Court on Thursday.
Sheriff Pender said: “I have to balance the various factors in this case.
“I realise you have had several major difficulties in your personal life and this has had an impact on your consumption of alcohol.
“There are strong mitigating factors but you were more than twice the limit, and it raises questions about whether you would have been able to carry out your job properly.
“While you have not been a commercial pilot for very long, you have vast skill as a US Air Force pilot and you must be aware of the dangers of flying under the influence of alcohol.
“You also deliberately flouted your employer’s guidelines and ignored what they regard as a safe eight-hour gap between drinking alcohol and being on duty.”
Grebenc pleaded guilty to performing “an activity ancillary to an aviation function” at stand 28 at Glasgow Airport while more than twice over the legal limit on August 27 last year.
The court heard that on the morning of August 27, Grebenc and his United Airlines colleagues were brought to Glasgow Airport from the Hilton Hotel in Glasgow, where they had spent the night, having flown from the US to Scotland the previous day.
They were due to fly a Boeing 757 to Newark with take-off scheduled for 9am.
As they passed through the staff search area, security staff smelled alcohol on the breath of the other First Officer, Carlos Licona, and raised the alarm.
Police were contacted and went to the departure gate, where Licona and Grebenc, also a US Air Force reservist, were removed from the flight.
Fiscal Depute Scot Dignan said: “Police did not go on board the aircraft as they wanted to be discreet and not alarm passengers.
“Grebenc was asked to disembark with Licona as police also had suspicions regarding him.
“He was taken to a quieter spot. At about 9.30am he was asked to provide a specimen of breath for analysis which proved positive and he was taken in a marked police vehicle to Govan police station.”
Later that day, he provided a blood sample for analysis, which showed he was more than twice the legal limit.
Licona was sentenced to ten months in prison earlier this month after he admitted boarding a flight while under the influence of alcohol.
The plane took off later that day with a new crew and 141 passengers on board.
David McKie, defending Grebenc, said his client was extremely remorseful.
He said: “He has asked me to express his remorse and apologises to the court and passengers for his irresponsibility and what was a significant misjudgment on his part.
“He takes full responsibility for his actions.”
Mr McKie told that court Grebenc is a former US Air Force pilot who flew an aircraft delivering fuel, including to war zones such as Iraq and Afghanistan, and carried out mid-air fuel transfers.
Alongside his commercial work with United Airlines, he still serves as a reservist with the US Air Force and has been involved in training young pilots.
His wife is also a pilot with the US Air Force and the couple, who live on an air base in Mississippi, have two children aged two and four.
Mr McKie told the court his client was under pressure at the time of the incident as there had been a recent family argument while two weeks previously doctors had found a shadow on his son’s lung which they feared might be cancerous, and the family had to wait until September to find out the prognosis.
He explained his client has been placed on the HIMS (Human Intervention Motivation Study) programme by his employers in conjunction with the federal aviation authority. The programme is geared towards rehabilitation.
The lawyer said the case would have “catastrophic consequences” for his client and could see him being dishonourably discharged from the US AIr Force and losing his pilot’s licence.
A United Airlines spokesman said: “We hold all of our employees to the highest standards. This pilot was immediately removed from service and his flying duties in August 2016.”