Mr. O'Leary referred to the minister as a “dunce” and suggested that he step down earlier this year. Unexpectedly, on May 13, Mr. O'Leary wrote to the minister to thank him for helping Ryanair get additional slots at Dublin Airport.

O’Leary wrote: “Dear Eamon, thanks for your help with these seats...”.

First, on May 10, Mr. O'Leary wrote to the head of the Green Party to let him know that Ryanair had just received word from the DAA that it would not be able to reserve more slots to accommodate spectators for the May 22 Europa League final, which would take place at the Aviva Stadium.

The Bergamo-based Atalanta and the Cologne-based Bayer Leverkusen team faced off in the final.

In order to accommodate the demand from football fans for flights into Dublin, Ryanair requested six more slots for Milan Bergamo and six additional slots for Cologne.

“Given your previous assurances that additional flights for sporting events would not be affected by Dublin Airport’s 32 million traffic cap, we were surprised and disappointed at midday today to be told that the DAA is refusing to approve these 12 additional midweek slots on the week of May 22 next,” O’Leary commented.