Colin McAllister and Justin Ryan, Scottish interior decorators and television hosts who were on the flight, said they were relieved that it had been delayed. “Counting blessings that @airtransat flight we were on did NOT take off yesty,” they wrote on Twitter from their joint account. “Thankfully someone spotted pilots behaviour.”

They added: “Better to arrive late in this world than early in the next. Boozing pilots?”

Sean Brown, a D.J. from Mississauga, Ontario, took to Twitter to thank the Scottish police for the arrests. “Just found out what ‘operational reasons’ means and I’d like to thank @ScotlandPolice for preventing a possible tragedy,” he wrote.

A spokeswoman for Police Scotland, who spoke on the condition of anonymity under agency protocols, said that the law in Scotland was very strict, and that even a “wee bit” of alcohol could result in prosecution. Under the law, she said, a pilot cannot exceed nine micrograms of alcohol in 100 millileters of breath on a breathalyzer test. Breaking the law can result in up to two years in prison.

Air Transat confirmed the arrest of two of its employees. “We will await the results of the investigation and judicial proceedings before commenting on the matter, before making any further comments,” it said in a statement. “The safety of our crews and passengers is, and will remain, a top priority at Air Transat.”

In the United States, the Federal Aviation Administration prohibits pilots from operating an aircraft if they have a blood alcohol content level of 0.04 percent or higher. Pilots are also prohibited from flying within eight hours of consuming alcohol.