One of the planes has just landed and was taxiing to the parking lot, while the second was preparing for departure.
During the towing, the Southwest Airlines plane preparing for a flight to St. Louis, Missouri, touched the wingtip of an identical airplane that was supposed to depart for Atlanta, Georgia.
Nobody was injured as a result of the incident. Judging from the picture, which one of the passengers made during the flight to Atlanta, the other aircraft had damaged the upper part of its vertical stabiliser.
After the collision, both aircraft were temporarily grounded for inspection.