Flight 2896 landed safely at Hobby Airport around 6pm. The plane had departed from Austin and was heading to Fort Lauderdale, Florida, when the pressure suddenly decreased and the oxygen masks dropped.
Southwest Airlines says 140 passengers and five crew members were aboard the plane at the time, but none of them were injured.
Southwest says it still does not know what caused the pressure to drop and is still inspecting the plane.
The passengers were placed on another flight for Fort Lauderdale.
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