It's 8.30am on Thursday and the boss of Europe's most successful low-cost airline should perhaps already be thinking of switching to decaff. "Nothing destroys the environment like two world wars. The idea that we're destroying the environment is nonsense. My cattle probably cause more carbon emissions than my fleet of aeroplanes." One of Ireland's richest men, O'Leary breeds Aberdeen Angus cattle and horses. He winks. "That'll get Guardian readers going."