(Reuters) - Aircraft engine maker CFM International said its backlog hit a record $180 billion last year as sales of fuel-efficient jetliners rose despite low oil prices and weakening economies that have raised concern about an aviation slowdown.

A visitor leaves a meeting room at the CFM International booth next to a LEAP high-bypass turbofan engine at the Singapore Airshow February 13, 2014. REUTERS/Edgar Su

CFM, a joint venture of General Electric Co GE.N and Safran SA SAF.PA of France, said its backlog rose to 13,400 engines, including 2,154 sales in 2015 valued at $27 billion.

The backlog of LEAP engines, which power Airbus AIR.PA A320neo and Boeing BA.N 737 MAX jetliners entering service this year and next, rose by 1,418 last year to total more than 10,000 units valued at $140 billion, the company said. CFM said it sold almost 600 engines last month.

Last year’s sales were about half the number booked in 2014, a record year. But CFM said demand is holding up even though the rationale for fuel savings is undercut by low oil prices and signs that the aircraft business cycle is peaking.

Those issues have raised concern that Boeing and Airbus may have to curb single-aisle plane production. Boeing said last month it will slow 737 output this year, but both Boeing and Airbus plan to boost output sharply over the next few years.

“For CFM, life is good,” Chief Executive Jean-Paul Ebanga said on a conference call ahead of the Singapore Airshow, which begins on Feb. 16.

“Not only are we confident today, but we are confident in the future,” he added, noting CFM is undertaking its largest testing program ever and working closely with suppliers to ensure stable production and cost controls.

His comments came after the Geared Turbofan engine made by Pratt & Whitney UTX.N, which competes with the LEAP, developed a glitch. Pratt has said it expects the problem, which requires a three-minute cooling procedure before the engine can be restarted under some circumstances, to be fixed this month.

CFM officials said on Friday the LEAP restarts in 50 seconds per engine.

The Pratt issue delayed delivery of the first A320neo by several weeks. Pratt and Airbus said on Friday they are in talks with customers about A320neo delivery schedules.

Pratt’s engine is available on the Airbus A320neo but not the 737 MAX.

CFM said it expects to build more than 140 LEAP engines and about 1,700 CFM56 engines this year. It confirmed it targets annual LEAP production of more than 2,000 by 2020, as reported by Reuters.