Irish Airline Pilots' Association (IALPA) is to carry out its own investigation into the bomb scare onboard a Ryanair flight.
IALP president Captain Evan Cullen said he had unconfirmed reports that the pilots were instructed not to disembark passengers on flight FR25 from Paris Beauvais to Dublin following its emergency diversion to Prestwick in Scotland yesterday afternoon.
The incident occurred after a note in a magazine was passed to the cabin crew, claiming there was a bomb on board.
Capt Cullen said pilots have a statutory obligation to ensure the safety their passengers and crew and it was "unusual" that an instruction not to disembark would be issued when there was a threat to the aircraft.
He said in recent years there had been an attempt to erode the authority of the pilot while holding him or her responsible for the security of the plane.
Two Royal Air Force fighter jets from the Coningsby base in Lincolnshire were scrambled at about 1.45pm to escort the Boeing 737 to Prestwick. A third Tornado jet from RAF Leuchars in Fife was also deployed.
The plane landed at Prestwick airport at about 2.20pm. The aircraft was searched, and nothing was found. It is not known who wrote the note.
After a nine-and-a-half hour delay, the Boeing 737 finally touched down in Dublin airport at around 11.30pm.
About 70 schoolgirls from Co Carlow were among the 172 passengers. Tears were shed as many of the girls were met by their parents in the airport.
Other passengers were furious at their treatment.
Passenger Charlie Fitzgerald, from Belfast, accused authorities in Scotland of violating civil rights and using the ordeal as a big security exercise. He said travellers were "left like lambs to the slaughter" as the aircraft was searched for more than two hours and the passengers were ordered to stay put.
"The crew were superb, and people weren't panicking," he said. "The pilot appealed and appealed to get us off the plane. He said later if a real bomb had been on board we would have been blown up to high heaven."
He added: "The whole thing was absolutely disgraceful. We had our pictures taken without permission, and statements were taken by police."
At Dublin airport, Jean-Jacque Niel was reunited with his 80-year-old mother, who had been travelling from her home in France.
Orla O'Connor, from Dún Laoghaire, was waiting for her brother Ronan (23), who is studying journalism in Paris. She said: "He has been sitting on a runway for nearly three hours and wasn't allowed to contact anyone until he had spoken to the police."
In a statement, Ryanair apologised "for any inconvenience caused to these passengers; however the safety of our passengers and aircraft will always be our number one priority".
The Department of Transport said it was monitoring events but would not be carrying out its own investigation.