The U.S. Air Force has awarded Boeing a $1.2 billion contract to build eight new F-15EX fighter aircraft.

The contract to Boeing includes the design, development, integration, manufacturing, test, verification, certification, delivery and modification of the F-15EX aircraft, including spares, support equipment, training materials, technical data and technical support, the Air Force said in a news release.

The two-seater fighters will be assembled in Boeing Defense’s special military facility in St. Louis, Boeing said. The first two jets are already under construction at the facility and are scheduled to be delivered during the second quarter next year, the Air Force said.

The new F-15EXs will replace older models of the F-15 fighter jets, which has U.S.-only capabilities, according to the Air Force.

Military officials said that the most significant difference between the new Boeing F-15EX and older F-15s involves its Open Mission Systems (OMS) architecture, allowing for it to include the latest aircraft technologies, including fly-by-wire flight controls, a new electronic warfare system, advanced cockpit systems and the latest mission systems.

In its own news release, Boeing said its F-15EX “carries more weapons than any other fighter in its class,” and can launch hypersonic weapons up to 22 feet long and weighing up to 7,000 pounds — a fact omitted from the Air Force’s news release.

“The F-15EX is the most advanced version of the F-15 ever built, due in large part to its digital backbone,” Boeing F-15EX program manager Lori Schneider said.

U.S. Air Force Gen. Mike Holmes, commander of Air Combat Command, said the Boeing F-15EX is the “most affordable and immediate way” to refresh his department’s air capacity and update the capabilities of aging F-15 fleets.

“The F-15EX is ready to fight as soon as it comes off the line,” Gen. Holmes said.

Another 12 of the F-15 EX fighters have been requested in the 2021 fiscal year budget, Boeing and the Air Force said.

The Air Force plans to purchase a total of 76 F-15EX aircraft as part of a five-year effort, called the Future Years Defense Program.

It’s the latest military win for the Boeing’s Defense unit.

Last month, Boeing won $3.1 billion worth of defense deals to produce two different missile weapon systems for foreign government buyers. The deals were for Harpoon and SLAM-ER, or Standoff Land Attack Missile Expanded Response systems. Boeing hasn’t made SLAM-ER missiles since the 2008 financial crisis.