Pratt & Whitney has secured a $3.8 billion contract modification covering lots 18 and 19 of the F135 engine, the powerplant for all variants of the F-35 Lightning II, bringing the total contract value to $6.6 billion.

The agreement confirms lot 18 propulsion system production while extending manufacturing to support lot 19 aircraft, reinforcing continuity across the F-35 programme’s supply chain.

“The F135 is the most advanced military engine in the world, delivering unmatched thrust, reliability and mission readiness for the United States and its allies,” says Jill Albertelli, president of Military Engines at Pratt & Whitney. “Pratt & Whitney is investing heavily across our global production base and supply chain to increase production and accelerate engine delivery and sustainment to meet growing global demand for the F-35 program.”

The company has invested more than $1 billion over the past five years to expand and modernise its production base, enabling a 20% increase in F135 output compared with earlier contract rates.

More than 1,400 production engines have now been delivered for the programme, which supports operations across 20 allied nations. The programme also sustains over 66,000 jobs across 47 U.S. states and territories and generated more than $9 billion in economic impact in 2025.