PARIS, Oct 17 (Reuters) - Mexican airline VivaAerobus is set to confirm next week an order worth up to $4 billion for 40 Airbus A320-family jets as it defects from Boeing to Airbus, industry sources said.
The selection, first reported by Reuters in June, follows a bitterly fought contest between planemakers as the Mexican low-cost carrier becomes the latest to compare updated fuel-saving models designed to enter service in mid-decade .
Airbus and Boeing declined to comment.
The deal is also expected to mark a breakthrough for United Technologies unit Pratt & Whitney, whose engines compete with GE/Safran venture CFM to power A320 jets.
VivaAerobus uses a fleet of CFM-powered 737-300s, an earlier generation of Boeing's most-sold passenger plane.
The Mexican carrier said in June it was studying proposals from planemakers about the possible purchase of new aircraft.