A Cold War-era U-2 spy plane was the cause of a major collapse in air traffic control systems in California which delayed hundreds of flights.
Thousands of flyers were delayed last Thursday after an air traffic control centre responsible for Los Angeles and Las Vegas suffered major problems with its tracking system.
The cause of the glitch had remained a mystery until yesterday, when aviation authorities confirmed it been triggered by a military U-2 flying over the area.
Although the high-altitude spy plane was flying at around 60,000 feet, well above civilian air traffic, the computer system mistakenly believed it was on a collision course with other aircraft.
The system became overwhelmed as it tried to route the plane to safety, forcing air traffic controllers to cancel flights and manually guide already-airborne craft to landing.
