International pilots' unions have said the forced landing of a Ryanair flight bore the hallmarks of state-sponsored hijacking and have demanded an independent inquiry.
Separately, the head of the Irish Air Line Pilots Association (Ialpa) said only a "very, very draconian" response along the lines of freezing European travel in and out of the east European state would suffice until solid reassurances were given that the incident would not be repeated.
"It's outrageous that a sovereign state would issue a hoax bomb threat to an airline. It's beyond the pale," said Ialpa president Capt Evan Cullen.
As a Polish-registered aircraft, Ialpa will not deal directly with the crew but Mr Cullen said that from what he could see of the aircraft's movements, it appeared they had made some effort to get to Lithuania as there was ongoing dialogue between the flight staff and the military aircraft.
He explained that if alerted to a possible onboard bomb, pilots are trained to carry out a controlled descent to avoid detonating a device designed to do so from a change in cabin pressure. It is not clear whether this was necessary in the Belarus incident, however.
“I would say it would be quite stressful but the pilots would know that they have to do their checks and that takes priority over how they might feel,” Mr Cullen said.
As an official EU response is awaited, Mr Cullen said some kind of restrictions on travel in Belarusian airspace would be likely.
“There will have to be some kind of reassurance from Belarus that their behaviour won’t be repeated and that people can trust what they are saying. It’s all about how the EU responds now.”
The International Federation of Air Line Pilots' Associations (Ifalpa) and the European Cockpit Association (ECA) said their members were concerned that the intervention of the Belarusian Air Force was enacted for political reasons.
Any such move is “in contravention of the Chicago Convention, and amounts to an act of unlawful interference, bearing all the hallmarks of state-sponsored hijacking,” it said.
“We are calling for an independent inquiry into this occurrence and appropriate immediate response by safety and security authorities.”
Crucially, the unions said the incident threatened to “upend” assumptions about the safest response to bomb threats on airlines in the absence of safe and reliable information from state and official services.
“The pilot-in-command always has the best overview of the actual situation on board and must be able to react according to the level of risk, regardless of external circumstances,” they said.
“Any military intervention against a civilian aircraft constitutes a wilful hazard to the safety of passengers and crew.”