‘If I were Boeing, would rebrand plane’: Trump on 737 Max crisis


He said Boeing's planned software update for the Max must "address the problem 100 per cent before we return the aircraft to air".

Southwest Airlines, meanwhile, removed 34 of the planes from their schedules this summer - which will result in 160 cancellations of some 4,200 daily flights between June and August.

But by extending cancellations through the summer, the airline can plan more reliably for the peak travel season, said Doug Parker, American's chairman and CEO, and Robert Isom, its president, in a letter to employees on Sunday (local time). Southwest Airlines, the largest operator of Boeing jets, announced last week that it would cancel its Max flights through August 5.

The aircraft was grounded worldwide in March after the fatal crash on Ethiopian Airlines which killed 157 people on board.

They added that the airline has been in close contact with the FAA, the Department of Transportation, the National Transportation Safety Board and global regulators and are "pleased with the progress so far".

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AA said that its reservations team will contact affected customers directly, with passengers on cancelled flights given the choice of rebooking or obtaining a refund.

Investigators are focusing on the plane's anti-stall software, the Manoeuvring Characteristics Augmentation System (MCAS).

Airlines are being forced to ground their planes longer than expected after Boeing and the FAA said the company needed more time to complete changes to a flight-control system suspected of playing a role in the recent crashes. US safety regulators have to approve the fix and decide on new training for pilots.

United Airlines, with 14 MAX jets, has largely avoided cancellations by servicing MAX routes with larger 777 or 787 aircraft, but the airline president, Scott Kirby, warned last week that the strategy was costing it money and could not go on forever.

"The FAA is preparing to make an announcement very shortly regarding the new information and physical evidence that we've received from the [Ethiopia crash site] and from other locations and through a couple of other complaints", Trump said.