Southwest Airlines has canceled hundreds of flights as it inspects 79 aircraft from its Boeing 737 fleet after one of its planes had to make an emergency landing with a gaping hole ripped in its fuselage, the airline has said.

The airline said it was canceling some 300 flights on Saturday, a day after the emergency landing, and could cancel around that number again on Sunday.

"We don't at this time know what the impact will be, but it's possible that it could be in the 300-flight range again," Southwest spokesman Brandy King told Reuters news agency.

Southwest normally has about 3,400 flights on Saturday, King said, so the cancellations accounted for nearly nine per cent of that total.

"We did our best to accommodate those passengers on other Southwest flights," King said.

Emergency landing

Passengers aboard Southwest Flight 812 from Phoenix to Sacramento on Friday heard a loud noise and the hole appeared suddenly at about mid-cabin, forcing the pilot to land at a military base in Yuma, Arizona.

The Southwest flight had 118 passengers and five crew members on board. One flight attendant and at least one passenger were treated for minor injuries at the scene, Southwest said.

Passengers described the harrowing scene to the CBS television affiliate in Sacramento.

"They had just taken drink orders when I heard a huge sound and oxygen masks came down and we started making a rapid descent. They said we'd be making an emergency landing," a woman identified as Cindy told the station.

"There was a hole in the fuselage about three feet long. You could see the insulation and the wiring. You could see a tear the length of one of the ceiling panels."

A total of 931 Boeing 737-300s are operated by all airlines worldwide, with 288 of them in the United States, the Federal Aviation Administration said.