Southwest Airlines has sent a team of mechanics to Victorville, California to start the long process of bringing its 34 Boeing 737 Max jets out of their desert hibernation, after the planes' permission to fly was restored.
How passengers will feel about flying in the aircraft is unclear, although Southwest customers' response to the Max in a recent survey was positive, executives said.
The US Federal Aviation Administration on Wednesday lifted a 20-month grounding of the Boeing 737 Max sparked by two crashes that together killed 346 people within five months and mandated a series of safety changes airlines must complete before the jets can fly with passengers again.
Low-cost carrier Southwest is the largest 737 Max operator in the world and was betting heavily on the aircraft to expand its business before the coronavirus pandemic sapped demand.
It still wants the jets, with about 15 per cent better fuel-efficiency than other 737 models, but will closely monitor customer response, executives said on a media call on Thursday.
"How each customer feels about making a reservation on a 737 Max or flying on a Max is an expression of personal comfort that we know is going to be different for every person," said Alan Kasher, senior vice president of Southwest's air operations.
Southwest does not plan to schedule 737 Max flights until the second quarter of 2021, and will allow anyone uncomfortable with flying the aircraft to rebook their flight at no charge.
A team of mechanics has already been keeping watch over Southwest's 34 jets in storage in Victorville, running the engines and systems on a regular basis, and a fresh team is now there to further "depreserve and exercise" the aircraft and complete the FAA's mandated changes, a process that will take about 280 hours, Mr Kasher said.
Once the FAA approves the work, the jets will fly to Southwest's main hangar cities for additional checks and maintenance. Meanwhile, its 8,000 pilots will receive fresh 737 Max training that will include about two hours in a simulator.