Planned to fly a Boeing Max 9? Here are your options.

After part of the fuselage of an Alaska Airlines Boeing 737 Max 9 jet blew out in mid-air on Jan. 5, minutes after takeoff from Portland, Oregon, the Federal Aviation Administration has grounded about 170 Max 9 planes held, forcing airlines that rely heavily on the planes to cancel thousands of flights and inconvenience many passengers.

On Wednesday, the FAA 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 flights with the Max 9s this week. Here's what passengers need to know about the plane and their rights if they don't want to fly.

Which airlines use the Max 9?

Of the 215 Boeing Max 9 aircraft flown worldwide, United Airlines operates 79, the most of any airline, and Alaska has 65, according to Cirium, an aviation data provider. Their combined fleets represent approximately 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 in general share detailed information about all aircraft in their fleets on their websites.

When will the airlines resume flying the Max 9?

Alaska said in a statement that final inspections, which last up to twelve hours for each aircraft, are underway. The airline said it planned to return the “first few aircraft” for scheduled flights on Friday.

United said in a statement that it was preparing Max 9 aircraft to return to service starting Sunday. However, the planes “could be used as a backup as early as Friday,” United Airlines spokesman Josh Freed said.

Copa, which grounded 21 Max 9 planes, said in a statement that it would “gradually restore flights that were previously canceled,” starting on Thursday and returning to a full schedule on Sunday.

How do I know if I have booked on a Max 9?

Travelers can usually find information about their aircraft 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 in an airline's mobile app in the details of their reservation after they book. For Alaska, this is available in the 'Details' section of the app. Flight tracking websites such as FlightAware also have aircraft information if users search for specific flights using the flight number.

But this is no guarantee. Even if passengers know in advance which aircraft they will fly, that is always subject to change. Airlines change planes at the last minute depending on factors such as weather and logistics.

What should I do if I don't want to fly a Max 9?

United and Alaska have both issued flight waivers due to the Max 9 inspections that allow passengers to cancel or change their flights without incurring fees. The Alaska Waiver applies to flights up to and including January 31. And United's exemption applies to flights through January 28.

Airlines have different policies regarding cancellations and refunds, depending on factors such as when you booked, how far in advance you want to cancel and what type of fare you purchased. Once the Max 9 waivers expire, passengers will no longer have the same rights to penalty-free rebookings or refunds for flights they choose to cancel.

For future bookings, Kayak has created a new filter that excludes up to 9 flights. This often means that you have to book with an airline 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 only airline that flies nonstop between Anchorage and Kona, on the Big Island of Hawaii. The airline has often used a Max 9 on this route, according to FlightAwarea flight tracking website.

But experts suggest there may be no point in avoiding the planes, which have been under strict inspections.

“It is not clear or rational why anyone would avoid the most recently inspected aircraft in the sky,” said aviation analyst Robert W. Mann Jr., emphasizing that the Max 8 was able to fly again several years later after two fatal crashes that killed 346 people .

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