Hundreds of flights were canceled or delayed on Monday — one of the country’s busiest travel days — after air traffic controllers were forced to switch to manual systems LONDON: British Transport Minister Mark Harper said it would take days to resolve the widespread disruption to flights into and out of the country after air traffic control systems were hit by a technical problem. Hundreds of flights were canceled or delayed on Monday — one of the country’s busiest travel days — after air traffic controllers were forced to switch to manual systems. Harper added that government officials did not believe the technical problem was the result of a cyberattack. “There is going to be some knock-on impact today and I suspect for another few days as airlines get their planes and get their services back to normal,” Harper told the BBC on Tuesday. Heathrow Airport, Britain’s busiest hub, told passengers on X, formerly known as Twitter, to contact their airline before traveling to the airport on Tuesday. Airlines said they were making changes to their schedules to try and fly as many people as possible but some planes and crews were not where they should have been. “We’re working as hard as possible to get affected customers on their way again,” British Airways said on Twitter.