(LONDON)— British Airways canceled all flights from London’s Heathrow and Gatwick airports for the rest of Saturday as a global IT failure caused severe disruption for travelers on a busy holiday weekend. The airline said it was suffering a “major IT systems failure” around the world. It didn’t say what was causing the problem but said there was no evidence of a cyberattack. BA said terminals at Heathrow and Gatwick had become extremely congested.