Strikes, air traffic control restrictions and bad weather forced easyJet to cancel 1,263 flights in June.
This compared with 213 cancellations experienced in the same month last year.
“Around 900 were due to French and Italian industrial action with a further 150 arising from ATC restrictions and adverse weather conditions,” the UK budget carrier said.
The airline saw passenger carryings rise by 2.3% to 7.9 million last month with the load factor up 0.5 percentage points to 95.4%.
Rolling annual passenger numbers were up by 6.6% to 83.3 million, excluding new operations from Berlin Tegal airport.