SINGAPORE—Cebu Pacific is moving closer to finalizing a major order for narrowbody aircraft, according to the carrier’s CEO Mike Szucs.

The airline still has a couple of months of negotiations to go with aircraft and engine manufacturers before making its choice and sealing a deal, Szucs tells Aviation Week on the sidelines of the Singapore Airshow. The order is likely to be announced in May or June, he says.

The order will encompass 100 firm orders with additional options, Szucs says. He stresses that both Boeing and Airbus are being considered.

While Cebu currently has an all-Airbus narrowbody fleet, this does not rule out a Boeing order, Szucs says. He notes that the development of a second major airport for Manila—in Bulacan—means Cebu may have a split-hub operation and could potentially have a different fleet at the new location. The current Airbus fleet is already large enough to achieve economies of scale.

“So I’m fine if it's Airbus, but I’m also fine if it's Boeing,” Szucs says. “What will drive the answer is what gives me the right economics.”

The airline will likely include different sized models within the order, Szucs says. This would mean the A320neo and the A321neo, or the 737-8200 and 737-10.

Cebu Pacific currently has 56 Airbus narrowbodies in its fleet, according to the Aviation Week Fleet Discovery database. It has another 27 on order, of which seven are due to be delivered this year. The airline also operates seven A330neos and one A330-300. It will be operating a fleet of 10 A330neos by the end of this year after new deliveries arrive, Szucs says.

The carrier currently has 10 of its narrowbodies grounded due to the Pratt & Whitney engine issue, Szucs adds. Cebu is forecasting this will rise to 15-16 aircraft on the ground at some point this year.

Cebu obtained more Airbus narrowbodies on short-term lease last year to help offset the engine-related groundings. Because of that, it expects to be able to maintain annual capacity growth of 10-12% this year.