Industry lifer rose from teenage pilot to BA boss
The British Airways boss is an airline industry lifer. He joined Aer Lingus as a teenager to train as a pilot before switching into management and was appointed chief executive in 2001.
He showed an aptitude for cost cutting and immediately axed 2,000 jobs and sold off some of the airline's assets, including its art collection.
But more significantly his task was to turn Aer Lingus into a low-cost airline that still also offered business class and transatlantic services and could compete against its arch rival, Ryanair.
He wanted Aer Lingus to be seen to be lean, but not necessarily mean and restored it to profitability.
In 2005, after a debate about its future ownership, he left and shortly afterwards got the top job at British Airways.
It was a big deal for a 'Paddy' to land the plum job at Britain's "favourite airline" and one of the world's largest carriers.
Mr Walsh has faced many challenges during his time at BA -- from the ash cloud that grounded its aircraft, to the shambolic opening of Terminal 5 at Heathrow and his bitter row with cabin crew. He oversaw British Airways' merger with Iberia to create the world's seventh-largest airline and Europe's third-biggest operator and he is now chief executive of the holding company, International Airlines Group.
It has more than 400 aircraft, flying to 200 destinations, carrying more than 62 million passengers a year.
Mr Walsh believes other European airlines will join IAG in the years ahead and that has led to speculation as to whether Aer Lingus will be one of them.
Last week, the group agreed to buy bmi from Lufthansa in a deal worth €350m and analysts are watching to see if it will bid for Portugal's national airline, TAP.
Mr Walsh and Mr O'Leary are friendly and the pair meet up every so often for a chat.