Ryan has a 40% stake and is believed to have invested roughly 40m in the airline, which is due to inaugurate flights in the next few weeks.

Tickets will go on sale this month.

It is the second major startup that Tony Ryan has become involved in within the past three years. The Ryan family already has a 16% stake in Singapore-based no-frills airline Tiger Airways. That holding cost 2.5m. Singapore Airlines also has a share in the carrier.

Former Ryanair executive and airline consultant Conor McCarthy also owns a stake in Aerobus. He also has a minority holding in Malaysia-based low-cost airline AirAsia, which competes with Tiger Airways on some routes.

Aerobus will begin operations with two leased aircraft and plans to fly between major Mexican cities and to some destinations in the United States.

Szucs, who served as COO at EasyJet for less than a year, left the company in June. He was a candidate to take over as chief executive of the airline, but the job went to Andrew Harrison.

Late last year Szucs sent a note to staff which said that EasyJet's "current profit level" was not good enough to justify its stock as a longterm investment. He said investors would be "much better off putting their money in the building society".

Conor McCarthy described the hiring of Szucs, who is expected to take up his post immediately, as a "significant coup" for Aerobus.