The US Federal Aviation Administration (FAA) has launched an investigation into an incident involving near-collision of two commercial aircraft at Chicago's Midway International Airport.
The incident occurred at around 7:40 pm (local time) on 16 June when two passenger jets tried to take off from intersecting runways.
According to a statement from FAA, the Southwest Flight 3828 flying to Tulsa, Oklahoma was cleared for takeoff and started on the runway, when Atlanta-bound Delta Air Lines 1328 also began taking off on an intersecting runway without necessary clearances.
The collision was averted after an on-duty air traffic controller saw both the planes approaching the intersection and shouted over the radio to the Delta flight to make the pilot stop. The aircrafts are said to have stopped 2,000ft from the runway intersection.
In a statement to ABC News, Southwest Airlines said: "Our reports indicate that after being cleared for takeoff at MDW on the evening of Tuesday, 16 June, the pilots of Southwest flight #3828 followed FAA Air Traffic Control instructions and safely aborted takeoff.
"Then, the pilots proceeded to taxi off of the runway to complete required checklist items and returned to the terminal to complete other necessary reports and tasks.
"The flight later continued onward to Tulsa without further incident."
Delta spokesman Morgan Durrant could not elaborate on what could have led to the confusion that resulted in the incident, but told the Associated Press that the airline was cooperating with FAA.