AUSTIN (KXAN) -- The Federal Aviation Administration (FAA) is investigating after a small plane "unexpectedly entered the flight path" of an American Airlines flight flying into Austin Bergstrom International Airport (AUS) Wednesday. This news comes as AUS expects a major travel day Monday following this weekend's F1 races. Last year, the airport recorded its busiest day on record that day. ‘Could have been catastrophic’: NTSB determines likely cause of 2023 near miss at Austin’s airport According to the agency, the crew on the American flight got an alert from air traffic control and adjusted its flight path. This put the American flight close to a second, small plane, and air traffic control "issued corrective instructions" to both of those planes. All three planes landed safely, the FAA said. According to Flightradar24, which tracks live air traffic, the plane that entered American's flight path got within 400 feet of the American plane. Ian Petchenik, the communications director for Flightradar24, explained the alert American got from air traffic control as "the aircraft yelling at you to do something now or you're going to crash into something." US congressman urges FAA addresses safety issues at Austin airport Petchenik said these cases are not common, but the alert process in place allows for these situations to end safely, as they did here. He said the plane that flew into American's flight path was not communicating with Austin's air traffic control tower. "If they had been, that controller would have told them not to be where they were," Petchenik said. He said any potential disciplinary action would be up to the FAA. The FAA said it is in the preliminary stages of the investigation. KXAN reached out to Congressman Lloyd Doggett's office about this matter. Doggett has expressed safety concerns about Austin's airspace in the past. KXAN will update this story when we receive a response.