OSLO (Reuters) - Airbus (>> Airbus Group) has delayed deliveries of its revamped A320neo jet by two to three months for additional tests of the Pratt & Whitney engines, the chief executive of budget carrier Norwegian Air (>> Norwegian Air Shuttle ASA) said on Thursday.

Industry sources told Reuters in February the plane-maker had told some airlines the A320neo delivery schedule had been pushed back by about two months.

"The A320 neo has some teething issues but we are working with Pratt & Whitney to solve the problems," an Airbus spokeswoman said on Thursday. "We are in constant discussion with our customers and we expect the problems to be solved by mid-year."

Norwegian, Europe's third-biggest low-cost airline by market capitalisation after Ryanair (>> Ryanair Holdings plc) and EasyJet (>> easyJet plc), has 100 of the new plane model on order and is scheduled to receive the first four in 2016 and eight more in 2017.

"The engines on the new neo planes require some more tests. It's always like that when new aircraft are being introduced," Norwegian Air Chief Executive Bjoern Kjos told Reuters on the sidelines of an earnings conference.

"The entire output is being delayed," he added.

Industry sources have pointed to delays in deliveries of the newly-developed Geared Turbofan engine from Pratt & Whitney, a subsidiary of United Technologies (>> United Technologies Corporation), as the cause of the problems.

On April 19, industry sources said more than two dozen A320neo jets without engines were crowding Airbus parking spaces and hampering its cash flow.

Despite its rapid growth, Norwegian Air so far relies purely on Boeing aircraft for its own operations, while leasing out Airbus planes to other companies.

Most of Norwegian's expansion is now taking place in long-haul, where it uses Boeing 787 Dreamliners to win market share on transatlantic routes and has promised one-way ticket prices as low as $69 (48 pounds) for flights from the United States to Europe.

Kjos said on Thursday the company could buy another 10 Dreamliners on top of the 40 it already has in operation and under delivery.

Norwegian on Thursday reported net earnings below forecast for the first quarter, while global oil prices extended a recent rise, sending the Oslo-listed company's shares down four percent by 0840 GMT.

(Reporting by Joachim Dagenborg, writing by Terje Solsvik, editing by Gwladys Fouche/Ruth Pitchford)