A Southwest Airlines flight dropped several hundred feet in a matter of seconds to avoid a midair collision, after the Federal Aviation Administration said pilots were alerted to another aircraft's presence in the area.

A Southwest flight out of Burbank rapidly descended 475 feet to avoid another plane on Friday, according to flight tracking data and passengers on the plane.

Southwest Airlines said in a statement that two flight attendants are being treated for injuries after the incident.

The passenger jet was responding to an alert of another aircraft in the vicinity, federal authorities said. A Cold War-era military plane was nearby at the time.