By Ben Kesling 
 

The aircraft engine unit of United Technologies Corp. (UTX) on Monday won a key order and took control of a joint venture central to its plans to double revenues from the business by 2020.

Pratt & Whitney unit will provide engines for the 50 Airbus A320neo jets ordered by Norwegian Air Shuttle ASA (NAS.OS) after winning a contest with rival engine maker CFM international--a unit of General Electric Co. (GE) and Safran SA (SAF.FR). Norwegian already has a fleet of Boeing Co. (BA) 737s powered by CFM engines.

"We chose the PurePower engine because we believe it offers the greatest long-term benefits in terms of reduced fuel burn and lower maintenance costs," said Norwegian Air Chief Operating Officer Asgeir Nyseth in a statement.

Pratt and CFM executives have sparred in recent days at the Farnborough International Air Show over the relative merits of the new, more fuel-efficient engines they are offering for the A320neo and the Boeing 737 Max. Boeing is only offering the CFM Leap engine on the revamped version of its best-selling jet.

In January, Norwegian announced it would be buying Airbus aircraft, a blow to Boeing and GE. This recent announcement charters more new territory for the Scandinavian low-cost airline, because it will now have two different types of aircraft in its fleet, as well as two different types of engines.

Pratt & Whitney also finalized on Monday plans to purchase the holding of Rolls-Royce Holdings PLC (RR.LN) share in International Aero Engines, raising its stake in the consortium to 61%.

Cebu Pacific Air (CEB.PH), a low-cost Philippine carrier, also announced Monday that it would buy Leap engines for the 30 Airbus A321neos it has on order.

Norwegian Air's new aircraft and engines are slated for delivery in 2016, and Cebu's for 2017.

Write to Ben Kesling at benjamin.kesling@wsj.com