London Heathrow Airport experienced flight delays on Sunday after staff shortages and bad weather led to limits on air traffic.

NATS, the UK’s airspace manager, said in an emailed statement that temporary restrictions were in place at Heathrow because of “short notice staff absence in the tower and strong winds.”

Heathrow isn’t the only UK airport that has been impacted by air traffic controller shortages this year. London Gatwick Airport said in late September that it had placed a cap on the number of daily flights through Oct. 1 because of the rising number of sick leaves.

Heathrow confirmed the news in a statement, adding that it encourages passengers to check the latest information with their airline. 

British Airways said it had to adjust some of its short-haul schedule and has apologized to affected customers and offered them the option to rebook their flight or receive a full refund. Its website showed dozens of flights delayed by up to two hours.

NATS said it was working with Heathrow and airlines to minimize disruption, and limits such as this were only imposed to ensure safety. The situation at the UK’s biggest airport is expected to improve in the afternoon, NATS added.