British Airways has called for an international treaty to track the whereabouts of surface-to-air missiles around the world after the downing of Malaysia Airlines Flight 17.
This came as the US Federal Aviation Administration restricted US airlines from flying at or below 30,000 feet (9,144 metres) over Iraq, citing a "potentially hazardous situation created by the armed conflict" there.
Some airlines already have bypassed Iraq on concerns that militants who control areas of the country may have anti-aircraft missiles.
Willie Walsh, the boss of BA's parent company, IAG, said British Airlines had stopped flying over the conflict region in eastern Ukraine in early March, based on publicly available information.
He would like to see the International Civil Aviation Organisation put pressure on the United Nations to organise a convention on surface-to-air missiles.
"At a minimum it would help to have a complete inventory of all the weapons, clearly identify which government had responsibility for managing those weapons, and facilitate a system for tracking where all those missiles are, simple measures that would improve the data and monitoring of those weapons," Walsh said.
He added: "One thing that clearly can be changed and could make a positive difference to airlines who have to undertake risk reviews would be greater and more transparent sharing of data and information with regard to security issues."
Asked if sharing information with Malaysia Airlines would have made a difference, Walsh said: "We'd like to think it should. But it wouldn't have changed the fact that the aircraft was shot down by rogue elements. That aircraft was flying in airspace that was open, was clearly identifiable as a civilian aircraft, and should not have been shot down."
In Ukraine yesterday, close shelling forced investigators into the downing of MH17 to cut short a visit to an area where some of the wreckage is lying.
"We heard at a distance of approximately 2km incoming artillery from where we were, and that was too close to continue," said Alexander Hug, deputy chief monitor with the Organisation for Security and Cooperation in Europe's mission in Ukraine.
Investigators had earlier said they had found body parts and personal effects of the victims.
"A number of remains were found," said recovery mission head Pieter-Jaap Aalbersberg.
Dutch and Australian police experts were at work for a second day with sniffer dogs helping them in the search for remains.
Those leading the investigation have warned that the task could take weeks to complete.
Additional reporting by Agence France-Presse