Ryanair is expected to confirm the purchase of 100 aircraft from US plane maker Boeing tomorrow at a press conference in London.
This will quadruple the size of its existing fleet of aircraft. A batch of 100 737 aircraft would be worth $6 billion at catalogue prices.
However analysts say the few carriers that can buy could expect very keen prices.
A spokesman for the company today would not say how many of the aircraft would be ordered or how many would be under options, but the carrier advertised last year for 50 second-hand 737s, implying an immediate willingness to introduce dozens of aircraft into its fleet.
Boeing and its European rival Airbus SAS have had little opportunity to sell aircraft since the September 11th attacks led airlines to slash capacity and park hundreds of surplus aircraft.
Earlier this week Ryanair confirmed again it was in talks to acquire several aircraft from suppliers as part of its long-term fleet expansion strategy.
A Ryanair spokeswoman said expanding the existing fleet, which currently stands at 39 Boeing 737, is part of the company's plan to cope with its increasing number of customers.
Ryanair carried 10.24 million people last year and is expecting a 25 per cent growth in passengers each year.
Additional reporting Reuters and PA
