Pratt & Whitney, a unit of RTX Corp. (NYSE: RTX), received a $6.6 billion contract for F135 engine production lots 18-19, according to a company statement. The engines power all three variants of the F-35 Lightning II aircraft.

The contract modification includes $3.8 billion for lot 18 F135 propulsion system production and provides for lot 19 F135 propulsion systems. The agreement covers full-rate production engines, initial spares, modules, engineering resources, program oversight and production support services for U.S. military services and international customers.

"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," said Jill Albertelli, president of Military Engines for Pratt & Whitney.

The company has committed more than $1 billion over five years to expand and modernize production capacity, resulting in a 20% increase in current F135 production rates compared to previous contract rates. Pratt & Whitney has delivered more than 1,400 production F135 engines for the F-35 program.

The F135 program supports over 66,000 jobs across 47 states and territories and generated more than $9 billion in economic impact domestically in 2025, according to the company. The F-35 program includes 20 allied nations worldwide.

RTX reported 2025 sales of more than $88 billion and employs over 180,000 people globally. The company is headquartered in Arlington, Virginia.