Monarch saw passenger numbers rise by 4.8% in March to more than 249,000.
The leisure scheduled airline carried 11,515 more passengers as 9,414 more seats were added. The load factor was up by 1.2% points to 87% year on year.
The top three routes last month were to Tenerife, Alicante and Malaga.
The monthly performance was boosted by the introduction of eight new routes to the Italian cities of Milan, Rome and Venice from a mix of four UK airports from March 25.