US authorities are investigating a runway incident involving two jets at New York’s Kennedy International Airport earlier this week.The two jets involved were Lufthansa Airbus 340 and an EgyptAir Boeing 777.When the Lufthansa flight was cleared for take off the EgyptAir pilot was asked to stop behind the "hold line" some 250ft from the runway, but when the pilot did not stop, air traffic controllers abruptly cancelled Lufthansa's take-off.It is unclear how close the two planes came but authorities say the Lufthansa flight stopped "a considerable distance" from the EgyptAir 777.One controller could be heard saying "that was quite a show, I thought it was going to be a short career".