International Air Transport Association (IATA) director general Alexandre de Juniac on Tuesday said he hoped a gathering earlier this week of regulators in Montreal would improve alignment over conditions to allow Boeing's 737 MAX jet to re-enter service.

At that meeting on Monday, the U.S. Federal Aviation Administration invited continued feedback from global regulators about the steps needed to return the grounded passenger jet to flight after two fatal crashes.

"We are permanently advocating in favor of an alignment among regulators, alignment on conditions, alignment on schedule for the re-entry into service of this aircraft," de Juniac told reporters Tuesday on a conference call.

"I hope (the meeting) will lead to a better alignment" even though he added the FAA has said that each country will make its own decision on when the MAX will fly again.

The closed-door meeting, on the eve of a United Nations aviation assembly in Montreal on Tuesday, brought together representatives from more than 50 countries with airlines that fly the MAX and those that will have incoming flights of the aircraft.

Airlines have urged regulators to coordinate with one another in a bid to avoid damaging splits over safety as they evaluate software changes undertaken by Boeing Co to return the MAX to flight.

Some countries have already vowed to run their own independent validation studies before restoring flights.

De Juniac warned that setting different conditions for re-entry of the MAX would "not improve the trust of the general public in the system," and create a situation where the aircraft could fly over some countries, but not others.

"You can have a situation where aircraft would be allowed to fly in some airspace and not in the neighboring airspace," de Juniac said.

The head of the global airline trade group also said a series of collapsing European carriers over the last 18 months, as well as British travel firm Thomas Cook, showed that the industry is "fragile."

"We are not a high margin industry, we are exposed to a lot of risks," he said.