"I held my kids. One was freaking out, crying," she said. "And so, we're trying to hold his hand and singing and praying a lot."
After the plane stabilised, the passenger said one of the pilots walked out of the cockpit and said one of the engines was lost, WCVB reported.
The plane landed safely at Pensacola in Florida.
A Southwest spokesman said its initial reports indicated no injuries were reported among the 99 passengers and five crew aboard.
The Wall Street Journal said photos taken aboard the flight showed the Boeing 737-700's engine inlet completely torn away, revealing extensive structural damage to the engine nacelle that hangs underneath the wing.
The spokesman said the failure caused a depressurisation of the cabin. The jet's fuselage, front edge of the wing, horizontal tail stabiliser and winglet were also damaged.
It was unknown what caused the failure.
