British Airways' system back online after worldwide outage

SAN FRANCISCO (KGO) -- British Airways says its computer systems are back online after a major system wide outage caused worldwide delays on Monday.

Thousands of travelers were waiting for hours for their flights out of San Francisco.

A London-bound flight from SFO left about four hours late on Monday. The airline's flight from Mineta-San Jose left three hours late.

"It went down around five o'clock, when we got here, and we've been in line three hours," traveler Erik Blangsted said.

"I think problems happen and you just got to keep calm and carry on," traveler Michelle Proudlove said.

The airline says passengers are being checked in at Heathrow and Gatwick airports on Tuesday, but the process may be a bit slower than usual.

Passengers are encouraged to check in online before getting to the airport.