On Thursday, Airbus revealed that Irish aircraft leasing company Avolon  signed a contract to purchase 20 of its next-generation A320neo aircraft in December. This contract added five aircraft to the 15-A320 order that Avolon inked with the company at last year's Farnborough International Airshow in July.

In a statement, Airbus characterized Avolon's upping its order size as "a clear recognition of the excellent value our products deliver." According to Airbus, new engines and "Sharklet" wing tip devices on the new plan make the new A320neo 15% more fuel efficient than the standard-issue A320, and help to add 500 nautical miles to the plane's flight range.

Financial details of the transaction were not disclosed. However, according to Airbus's official price list for 2012, the A320neo averages $96.7 million, making the total purchase price of approximately $1.9 billion at list prices -- or $483.5 million more than Avolon had initially planned to spend.