Northrop Grumman reports it has delivered its 150th center fuselage for the F-35 Lightning II Joint Strike Fighter to Lockheed Martin.

The fuselage, designated AF-68, will be integrated into a conventional takeoff and landing variant of the aircraft at a Lockheed Martin's F-35 assembly facility in Texas.

Northrop Grumman said the fuselage delivered earlier this month was the 50th produced by the company over the past 15 months and symbolizes the company's ratcheting up of production -- it's first 100 fuselages took more than eight years to produce from the start of the program.

"The delivery of AF-68 represents Northrop Grumman's steady progress reducing the production time for the F-35 center fuselage," said Brian Chappel, vice president and F-35 program manager, Northrop Grumman Aerospace Systems. "It also maintains the company's perfect record of on-time deliveries of center fuselages from our Palmdale manufacturing center to Lockheed Martin."

According to Chappel, the increase in the production rate is a result of Northrop's integrated assembly line, which opened in 2011 and makes heavy use of robotics.