How to Know if You’re Scheduled on a Boeing 737 Max 9, and What Your Options Are

After a portion of an Alaska Airlines Boeing 737 Max 9 jetliner’s fuselage blew out in midair minutes after taking off from Portland, Ore., on Jan. 5, the Federal Aviation Administration grounded about 170 Max 9 planes, causing airlines that rely heavily on the aircraft to cancel thousands of flights and inconveniencing many passengers.

On Wednesday, the F.A.A. approved inspection and maintenance procedures for the planes, clearing the way for the grounded Max 9 planes to fly again.

Airlines said they planned to resume flying the Max 9s this week. Here’s what passengers should know about the plane and their rights if they want to avoid flying on it.

Which airlines use the Max 9?

Of the 215 Boeing Max 9 airplanes flown globally, United Airlines operates 79, the most of any airline, and Alaska has 65, according to Cirium, an aviation data provider. Their combined fleets represent about 70 percent of the Max 9 jets in service.

Other operators relying on the Max 9 include Panama’s Copa Airlines, Aeromexico, Turkish Airlines, FlyDubai and Icelandair.

Airlines generally share detailed information about all the planes in their fleets on their websites.

When will the airlines resume flying the Max 9?

Alaska said in a statement that final inspections, which take up to 12 hours for each plane, are underway. The airline said that it planned to bring the “first few planes” back for scheduled flights on Friday.

United said in a statement that it was preparing Max 9 planes to return to service beginning on Sunday. However, the planes “may be used as spares” as soon as this Friday, said United Airlines spokesman Josh Freed.

Copa, which grounded 21 Max 9 planes, said in a statement that it would be “gradually reinstating flights that had previously been canceled” beginning on Thursday and returning to a full schedule on Sunday.

How can I tell if I am booked on a Max 9?

Travelers can typically find information about their plane type when they book their flights online, either during the seat-selection process or elsewhere on the airline’s website.

Passengers may also be able to find the aircraft type on an airline’s mobile app, in the details of their reservation after they’ve booked. For Alaska, this is available in the app’s “Details” section. Flight tracking websites, such as FlightAware, also have plane information if users search for specific flights using the flight number.

But this is no guarantee. Even if passengers know in advance what plane they are scheduled to fly on, that is always subject to change. Airlines swap out aircraft at the last minute, depending on factors such as weather and logistics.

What if I don’t want to fly on a Max 9?

United and Alaska have both issued flight waivers because of the Max 9 inspections that allow passengers to cancel or change their flights without incurring fees. Alaska’s waiver applies to flights through Jan. 31. And United’s waiver is for flights through Jan. 28.

Airlines have varying policies covering cancellations and refunds, which depend on factors such as when you booked, how far in advance you want to cancel, and what type of fare you have purchased. Once the Max 9 waivers expire, passengers won’t have the same rights to penalty-free rebookings or refunds for flights they opt to cancel themselves.

For future bookings, Kayak has created a new filter that excludes Max 9 flights. That would often mean booking on a carrier that does not use the planes. But on certain routes with a limited number of carriers, that may not be an option. For example, Alaska is the sole carrier flying nonstop between Anchorage and Kona, on Hawaii’s Big Island. The airline has often used a Max 9 on this route, according to FlightAware, a flight tracking website.

But experts suggest it may not make sense to avoid the planes, which have been under rigorous inspection.

“It’s not clear or rational why anyone would avoid the most recently inspected aircraft in the sky,” said the aviation analyst Robert W. Mann Jr., emphasizing that the Max 8 resumed flying several years after two deadly crashes that killed 346 people.

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