Two pilots scheduled to fly 141 people from Glasgow, Scotland to Newark, New Jersey, were removed from service prior to takeoff on Saturday and arrested on suspicion of being intoxicated.
In a statement to BuzzFeed News, Police Scotland confirmed that the two men aged 35 and 45 were currently in police custody.
The pilots are expected to be arraigned on Monday to face charges of carrying out their duties while exceeding the prescribed limit of alcohol, a violation of Section 93 of the Railways and Transport Safety Act, according to a police spokesperson.
“We are cooperating with authorities and will conduct our own investigation as well,” United spokeswoman Erin Benson told BuzzFeed News. “The safety of our customers and crew is our highest priority."
Benson said the 757 eventually departed 10 hours late when a new assigned crew arrived to fly the passengers to Newark.
During the wait, a passenger complained on Twitter of not being provided with any information about the reason for the delay.
But United said they have since apologized to customers for the inconvenience and provided them with meal and hotel vouchers when required.
In January, a pilot with Alaska Airlines was charged after a reading of his breath showed an alcohol level of 0.134 when he flew passengers on two flights from San Diego and Portland in 2014.
A co-pilot for American Airlines was detained in May at Detroit’s Metropolitan Airport after allegedly preparing to fly a plane while drunk. Passengers snapped photos of the pilot being arrested on the tarmac.