The Federal Aviation Administration has confirmed that a Soviet-era U-2 spy plane operated by the Air Force was partly responsible for major flight disruptions in California last week. According to a statement obtained by NBC News, air traffic computer systems "experienced problems while processing a flight plan filed for a U-2 aircraft that operates at very high altitudes under visual flight rules." The U-2 was flying at its proper altitude of 60,000 feet when it crossed into airspace monitored by the Los Angeles Air Route Traffic Control Center on Wednesday afternoon. But for reasons unknown, air traffic computers apparently saw it as a risk for commercial flights flying far below. "The computer system interpreted the flight as a more typical low altitude operation, and began processing it for a route below 10,000 feet," the FAA said.

Since the system incorrectly assumed the U-2 was on a collision course with other planes, it next tried to come up with new routings that would safely "de-conflict the aircraft with lower-altitude flights." But the FAA said this taxing process "used a large amount of available memory and interrupted the computer’s other flight-processing functions." With its computer systems scrambled, the FAA was forced to issue a ground stop order that impacted tens of thousands of travelers.

LAX felt the brunt of that decision; the busy airport reported 27 cancellations, 212 delays, and 27 diversions to other airports. The ground stop was lifted after an hour or so. The system that experienced the sudden overload now requires "specific altitude information for each flight plan," according to the FAA, a step it's confident will prevent the situation from repeating itself. And that's a good thing, since the unexpected shutdown could have caused a crisis if there had really been unforeseen circumstances in the air.