Boeing has won about $1.2 billion contract from the U.S. Air Force to build the first lot of eight F-15EX advanced fighter jets to help the service meet its capacity requirements and add capability to its fighter fleet.

The new contract also covers support and one-time, upfront engineering costs.

In addition, the U.S. Air Force has awarded Boeing with the overall Indefinite Delivery Indefinite Quantity contract worth upto $23 billion for F-15EX.

The first eight F-15EX aircraft would be fielded at Eglin Air Force Base, Florida, to support testing efforts. The delivery of the first two aircraft is scheduled for the second quarter of fiscal 2021. The remaining six aircraft are scheduled to deliver in fiscal 2023.

The F-15EX would replace the oldest F-15C/Ds in the service's inventory. The Air Force has planned to purchase a total of 76 F-15EX aircraft over the five-year Future Years Defence Program. Eight F-15EX aircraft were approved in the fiscal year 2020 budget and 12 were requested in the fiscal 2021 budget.

"The F-15EX is the most affordable and immediate way to refresh the capacity and update the capabilities provided by our aging F-15C/D fleets," said Gen. Mike Holmes, commander of Air Combat Command. "The F-15EX is ready to fight as soon as it comes off the line."

The company boasted that the F-15EX carries more weapons than any other fighter in its class, and could launch hypersonic weapons up to 22 feet long and weighing up to 7,000 pounds (3,175 kg).