The plane, Southwest Flight 3472, on Saturday diverted to Pensacola when the crew declared an emergency, CNN quoted the Federal Aviation Administration (FAA) as saying.
The airlines which is also the world's largest low-cost carrier, described the engine trouble as a mechanical issue.
A woman who was on the plane on Saturday with her husband and three children told CNN that the engine was right outside her window.
"It was just a big explosion. There was some smoke and then nothing," she said, addinf "I saw parts flapping in the wind."
The plane started shaking and breathing masks were deployed as the airliner descended.
None of the 99 passengers or five crew members was hurt, CNN reported citing Southwest Airlines as saying.
The FAA and the National Transportation Safety Board have launched a probe.
