SEATTLE (Reuters) -A group representing global airlines has asked the U.N.'s aviation agency to raise the international age limit for commercial pilots to 67 years from 65, saying worldwide demand for air travel is outstripping the supply of aviators.

The U.N.'s International Civil Aviation Organization (ICAO) will consider the proposal, which has been opposed by major U.S. pilot unions, at its General Assembly that convenes on September 23. 

International rules prohibit airline pilots older than 65 from flying international flights, and many countries, including the United States, apply the same rule domestically as well.

The International Air Transport Association (IATA), which represents about 350 airlines, said raising the limit by two years is a "cautious but reasonable step consistent with safety."

There would still have to be at least two pilots operating each flight, including one younger than 65 if the other pilot is above that age, IATA said in a working paper published on ICAO's website. 

In 2006, ICAO lifted the age limit from 60 to 65.

The major pilot unions in the U.S. have opposed a higher retirement age based on safety concerns.

There is not enough data available to adequately understand the risk of increasing the retirement age, said Allied Pilots Association (APA) spokesperson Dennis Tajer, an American Airlines pilot.

"We don't gamble with safety that way," he said.

The Air Line Pilots Association and the Southwest Airlines Pilot Association did not immediately respond to requests for comment. 

U.S. pilot unions opposed an unsuccessful push backed by U.S. carriers in 2023 to get Congress to raise the mandatory airline pilot retirement age to 67 from 65.

A bipartisan group of lawmakers in Congress last month pushed President Donald Trump's administration to support international efforts to raise the mandatory pilot retirement age.