Wizz Air saw passenger numbers rise by 22.5% in June to 5.3 million.
The year-on-year rise came as the budget carrier increased capacity by 14.3% to offer more than 5.7 million seats last month.
The load factor was up by 6.1 percentage points to 92.2% as more seats were filled.
Meanwhile, Ryanair saw numbers increase by 9% to 17.4 million passengers from 15.9 million in June last year, with the load factor static at 95%.
The improved carryings at Wizz Air came in a month when the eastern and central European low cost airline forecast that its entire fleet of aircraft based at Luton airport would be new generation Airbus A321neos by 2025.
Wizz Air also announced 10 new winter routes from Tirana in Albania including to Birmingham, Edinburgh and Liverpool.
The airline tookdelivery ofitslatest A321neo from an Airbus assembly plant in Tianjin, China.