(Adds future production numbers, background)
By Mike Stone
WASHINGTON, Dec 20 (Reuters) - Lockheed Martin Corp said on Thursday it has reached its 2018 target to deliver 91 F-35 fighter jets to the United States and its allies, as the defense contractor built 38 percent more jets this year.
The F-35 accounts for about a quarter of Lockheed's total revenue. During the third quarter, F-35 production volume and payments for maintenance increased in the quarter.
The cost of the most common variation of the jet, the F-35A, is now $89.2 million after the most recent round of contract negotiations announced in September.
Lockheed Martin said that in 2019 it aims to deliver more than 130 F-35s representing a 40 percent increase in production over 2018. The Bethesda, Maryland-based weapons maker is aiming for annual production to more than 160 jets in 2023.
In November, Lockheed received $6 billion in funding towards a multiyear commitment on a batch of 255 jets from the United States and its allies.
This year, more international customers have signed on to buy the jet. In October, Belgium said it chose the F-35 over the Eurofighter Typhoon to replace its ageing F-16s in a 4 billion euro ($4.55 billion) deal.
Other U.S. allies have been eyeing a purchase of the stealthy jet. Potential new customers include Finland, Germany, Spain, Switzerland, the United Arab Emirates.
Despite the consistent growth, the F-35 has been widely criticized for being too expensive, including by U.S. President Donald Trump and other U.S. officials, who have also pointed to numerous production delays and cost overruns.
Earlier this year, all Lockheed Martin's U.S. and international F-35 fighter jets were grounded for engine inspections following a crash of an F-35B on Sept. 28 near Beaufort, South Carolina. (Reporting by Mike Stone in Washington; Editing by Alistair Bell and Grant McCool)