(Reuters) - U.S. airlines that operate the 737 MAX - Southwest Airlines Co, American Airlines Group Inc and United Airlines - said their focus following the plane’s grounding was on finding alternatives for affected customers as quickly as possible.

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The United States on Wednesday joined other countries in grounding Boeing’s 737 Max after an Ethiopian Airlines plane crash on Sunday that killed 157 people, the second disaster involving the plane in less than five months.

Southwest is the world’s largest operator of the 737 MAX 8 with 34 jets, or about 5 percent of its total fleet. American flies 24 MAX 8s and United 14 MAX 9s, which represents three percent of the airlines’ respective fleets.

The numbers add up to the second largest fleet of 737 MAX planes in the world by country after China’s 97, according to data from Cirium’s Fleets Analyzer as of March 11.

The airlines provided further details in statements to Reuters, below. They also asked customers to check their websites for updates.

SOUTHWEST AIRLINES

“While we remain confident in the MAX 8 after completing more than 88,000 flight hours accrued over 41,000 flights, we support the actions of the FAA (Federal Aviation Administration) and other regulatory agencies and governments across the globe that have asked for further review of the data – including information from the flight data recorder – related to the recent accident involving the MAX 8.

“Any customer booked on a canceled MAX 8 flight can rebook on alternate flights without any additional fees or fare differences within 14 days of their original date of travel between the original city pairs.”

AMERICAN AIRLINES

“American Airlines has 24 aircraft affected by this directive.

“We appreciate the FAA’s partnership, and will continue to work closely with them, the Department of Transportation, National Transportation Safety Board and other regulatory authorities, as well as our aircraft and engine manufacturers. Our teams will be working to rebook customers as quickly as possible, and we apologize for any inconvenience.”

UNITED AIRLINES

“Since Sunday, we have been working diligently on contingency plans to prepare our fleet to minimize the impact to customers. Our MAX aircraft account for roughly 40 flights a day and through a combination of spare aircraft and rebooking customers, we do not anticipate a significant operational impact as a result of this order.”

For cancellation data flightaware.com/