At first glance, the image that flashed on the 19-inch computer screen looked like an ordinary road map. The manager began to tap at his keyboard. With one tap he produced on the screen a view of the entire New York Metropolitan area. Then with another one he removed hundreds of tiny black dots showing the location of private aircraft. What remained on the screen were large, winged symbols representing commercial aircraft. He marked the jetliners with different colors according to their airport destination by tapping a few more keys. Red was for La Guardia Airport and brown for John F. Kennedy Airport.