Flight disruption caused by UK air traffic control failures could linger for days ahead.
Transport secretary Mark Harper said there is no quick fix.
Bank holiday Monday flights were in disarray after a UK air traffic control IT failure.
Air traffic controllers were forced to log flight plans manually.
Harper said there was no evidence of a cyber-attack.
“There was a technical issue with the flight planning system that will be looked at in detail,” he said.
According to flight data from Cirium, 790 flights were cancelled at UK airports on Monday.
This represents 27% of all scheduled departures.
A similar number of arriving flights were also cancelled.
Heathrow was hardest hit for cancelled flights followed by Gatwick and Manchester.
“I accept it has disrupted thousands of people. Lots of flights were cancelled to keep the system working safely,” Harper said.
‘It is going to take some days to get completely everybody back to where they should
