LA air traffic controllers have warned Qantas that unless changes are made, they may have to turn away the world's largest passenger planes.

According to a report in the Daily Telegraph newspaper, America's National Air Traffic Controllers Association said Los Angeles airport would not be able to accommodate the A380 if not for the recession-related slump in air traffic.

"It is pretty inconvenient moving that Airbus around the airport," the association's LA tower president Mike Foote said yesterday. "There are restrictions that apply to that aircraft that don't apply to others."

The A380's wingspan is too wide for the existing runway and whenever one landed all ground traffic had to be stopped he said.

"They are 50ft (16m) wider than any other aircraft we have so it causes all sorts of problems," Mr Foote said.

Qantas has been flying the A380s from Melbourne and Sydney to LA since October. As Australia's national carrier, Qantas has invested heavily in the new planes and plans to have seven flying by the end of this year. They cost about $350 million each.

A Qantas spokesman said the company was working with the LA airport to improve its infrastructure.

"The city has always been fully aware of our requirements and of the economic benefits our A380 operations bring," said the spokesman. "Airports need to be able to handle these larger aircraft and we are working with the airport to develop longer-term infrastructure improvement options."

Qantas is the only airline running A380s at LAX.