An air traffic controller had to tell the jet to stop after realizing that the United plane was taxiing on the same runway The planes were reportedly just over a quarter mile apart when the pilot on the Republic jet hit the brakes An investigation has been opened after a Republic Airlines jet had to hit the brakes to avoid a collision with a United Airlines plane at LaGuardia Airport in New York City.

Officials are investigating why two planes got dangerously close on a runway at LaGuardia Airport despite the airport being equipped with a system that's designed to help prevent such close calls.