Strathclyde Police in Scotland has defended its response to the weekend bomb hoax on an Aer Arann aircraft which was diverted to Prestwick airport outside Glasgow.
The Irish Airline Pilots' Association (IALPA) has called on the Department of Transport to clarify whether the British authorities have changed their security procedures or are "making it up as they go along".
The 48 passengers on Friday's Aer Arann flight, originally bound from Luton to Galway, were not allowed to disembark until 90 minutes after the aircraft had landed at Prestwick.
Just two days before, passengers on a Ryanair Paris to Dublin flight, which was diverted to Prestwick in a similar bomb alert, were also prevented from disembarking for more than two hours after landing.
Strathclyde Police is leading the investigation into the hoax, which precipitated the second major security alert in British airspace in three days - with both incidents involving aircraft bound for Ireland.
A police spokeswoman said the decision to retain passengers on board was as a result of a "full risk-assessment carried out by Strathclyde Police", and the safety and wellbeing of passengers was a priority "at all times".
If passengers were in immediate danger, they would have been "immediately evacuated" from the aircraft, the spokeswoman said.
The alarm was raised some 40 minutes into flight RE508 from Luton, London, to Galway on Friday night, when a cabin crew member was alerted to writing on the back of a passenger's food tray in row 12.
The writing resembled "graffiti", according to several passengers sitting nearby, who spoke of their ordeal after landing at Galway airport on Saturday afternoon. An arrow beside the word "bomb" appeared to be "pointing down", according to Michael Hunt, from Athenry, Co Galway.
"Everyone was very calm. My wife is pregnant and there was a lady with a young child on board, but the staff behaved impeccably," said Mr Hunt, who is director of the Theatre Royal in Waterford.
However, it was a "very distressing situation", exacerbated the fact that the passengers were "left sitting in an airport with a potential bomb on the plane for one-and-a-half hours".
Initially passengers were told that the aircraft would land in Liverpool, but it was then diverted to Prestwick under RAF Tornado escort. Prestwick, some 30 miles south of Glasgow, is one of two British airports designated to deal with such alerts due to its distance from a large conurbation.
Seán Mac Sheamais, a business analyst from Furbo, Co Galway, said that he had made a formal complaint about the response. "If there was a threat to the aircraft, Irish citizens were put in danger."
Passengers including Mr Mac Sheamais and Kathy Doherty, from Athenry, described how they were escorted by "between 20 and 30 armed police" in a bus to the airport. They were interviewed individually in the early hours of the morning, each passenger had to sign a written statement and they were photographed with a number identification for police records.
"We were treated like criminals," Mr Mac Sheamais said.