WASHINGTON — Government and aviation industry officials from dozens of countries are meeting in Montreal this week to try to find consensus on how to keep from losing airliners like the one that vanished without a trace in Asia and another shot down in Eastern Europe.

It is only the second high-level safety conference in the 70-year history of the International Civil Aviation Organization, a U.N. agency, but last year was calamitous. A Malaysia Airlines flight disappeared in March and has not been found. In July, another Malaysia Airlines flight was down shot down while flying over an area of Ukraine where ethnic Russian rebels are trying to secede.

There is broad agreement that the agency should build a database where governments can send intelligence or warnings about risks to aircraft flying over conflict zones. Historically, though, nations other than the United States rarely have posted public warnings about such risks in other countries. Few have global intelligence networks, and it has been considered almost impolite for one country to issue a warning about another. Instead, the practice has been for each country to issue warnings only about its own airspace.

But that is changing.

ICAO, the U.N. agency, sent an urgent warning to members on Jan. 14 that airlines flying over Libya risk being shot down. On Jan. 22, the European Aviation Safety Agency distributed a French warning that flights over Pakistan might be subject to “terrorist attacks.”

Ukraine had warned airlines flying over its territory to remain above 32,000 feet. The Malaysia plane, however, was flying at about 33,000 feet from the Netherlands to Kuala Lumpur, the Malaysian capital, when it was fired upon.

Most of the 298 people aboard were Dutch citizens. The Netherlands wants airlines to tell passengers before takeoff of a plane’s flight across a conflict zone. Airlines and other nations say that goes too far.

While sympathetic to the Dutch concerns, “we’re also confident that an ICAO centralized database represents a reasonable balance,” said Kenneth Quinn, former counsel at the Federal Aviation Administration.