One of the planes was a Paris-bound Air France A380 -- one of the largest in the world -- which was carrying 500 passengers. While on its way to the runway for takeoff, it somehow ran into a taxiing Comair plane that had landed and was heading to the gate.
It not yet clear why the pilots were unaware of their proximity to each other. Investigators have already begun interviewing passengers to try and piece together what happened.
No one was injured in the collision, but both planes were damaged in the accident.
The Air France flight was diverted to Terminal 1, the Comair plane to Terminal 2. Comair is the regional carrier for its parent company, Delta.