The recent IT disruption affected the company's workforce rostering system and 64 holiday flights operated by TUI were grounded during the weekend. A spokesperson for TUI said: “Due to the global IT issue at airports and airlines around the world on Friday, TUI’s overall service this weekend was heavily impacted and we would like to apologise to everyone affected.“Whilst the original IT issue was outside of our control, the impact to our systems on Friday has meant that our flight programme has suffered continued delays that we have not been able to resolve.