Southwest Airlines

The pilots say they stand to lose $100 million in income. Southwest has canceled more than 30,000 flights since the FAA grounded the aircraft in March after two crashes killed 346 people.

The FAA says the issue that affected Southwest, Delta and other carriers has been resolved. But with hundreds of flights affected, the delays could linger.

Some U.S. airlines are scrambling to rebook passengers after the FAA announced it was grounding the Boeing 737 Max fleet. Airlines affected include Southwest, American and United.

The carrier says the Aircraft Mechanics Fraternal Association "has a history of work disruptions." The union says the airline is "scapegoating" its technicians.

Peanuts have long been a part of Southwest's marketing campaigns. The carrier says it is ditching the snack to protect passengers with peanut allergies.

There were no injuries aboard the Boeing 737, but the incident startled passengers and caused the pilot to make an unscheduled landing in Cleveland.

On April 17, an engine that exploded caused the death of one passenger and injured others. A survivor has filed a lawsuit against the carrier, alleging she now suffers from PTSD and other conditions.

The Federal Aviation Administration says CFM engines, which power many Boeing 737s, need to be ultrasonically inspected after a certain number of takeoffs and landings.

"We have a part of the aircraft missing, so we're going to need to slow down a bit," the pilot told air traffic controllers as she prepared to land with nearly 150 people onboard.

At a House Transportation and Infrastructure Committee hearing on airline customer service, representatives expressed their personal frustrations with the vagaries of flying on U.S. airlines.