EasyJet saw passenger carryings top 6 million last month despite increased levels of flight cancellations due to air traffic control strikes in France.
The budget carrier was forced to ground 602 flights in April against 48 cancellations in the same month last year.
The number of passengers flown increased by 3.8% year-on-year from 5.7 million.
The passenger load factor rose by one percentage point to 90.8%.
April’s figures mean that annual carryings to April were up by 6.2% to 66.2 million.
Meanwhile, central and eastern European low-cost rival Wizz Air reported a 21% rise in passengers carried in April to more than 1.7 million with an improved load factor of 86.2%, up 1.7 percentage points on the same month last year.
The number of passengers carried by Aer Lingus in April dropped by 5.2% year-on-year to 923,000.
Short-haul numbers dropped by 5.5% to 710,000 while long haul carryings rose by 1.8% to 113,000.
The load factor increased by 2.4 percentage points to 78.2%.
Aer Lingus Regional traffic dropped by more than 10% to 100,000.
Scandinavian low-cost carrier Norwegian managed to increase carryings in April despite suffering from the impact of a pilots strike.
The airline said its traffic figures for April were influenced by repercussions from the industrial action by pilots in Scandinavia and an earlier Easter.
Norwegian carried 2.1 million passengers in April, an increase of seven percent compared to the same month last year.
The load factor was up by 2.6 percentage points 82.4% as capacity rise by 11% with the delivery of a new Boeing 787 Dreamliner, bringing its long haul fleet up to eight aircraft.
Chief executive Bjørn Kjos said: “The pilot strike in Scandinavia also had an impact on April’s traffic figures. But we are pleased that – in spite of this – the load factor is better than the same period last year.
“We are especially pleased that we continue to attract many new customers in Europe and USA, which proves that our international strategy works.”