History
Development History
In the 2010s, the United States Air Force faced significant challenges with its fighter fleet modernization. The current size of the F-22A Raptor fleet proved inadequate to completely replace the aging F-15C/D Eagles. Originally, the USAF had planned to acquire 381 F-22A Raptors to replace its F-15C/D fleet, but post-Cold War budget cuts following 1991 reduced this number to just 187 aircraft by 2009. This reduction coincided with the Department of Defense’s strategic shift toward asymmetric counterinsurgency warfare during the War on Terror.
Restarting F-22A production became politically impossible due to prohibitive costs associated with rebuilding production lines and sourcing replacement parts. Compounding these challenges, delays in the F-35 Joint Strike Fighter program left the Air Force without sufficient modern fighters to replace its aging fleet on schedule.
These operational gaps forced the USAF to develop an alternative strategy for maintaining air superiority while finding a way to field adequate numbers of modern fighters. The service decided to modernize and retain its F-15C/D fleet, extending their service lives into the 2030s, well beyond their originally planned retirement dates. The modernization program mandated several critical upgrades, including a new AESA radar, an IRST system, and the advanced Eagle Passive/Active Warning Survivability System (EPAWSS).
Following McDonnell Douglas’s merger with Boeing, the company had been actively developing advanced F-15 upgrades for international customers, including the F-15SA for Saudi Arabia and F-15QA for Qatar. Recognizing this expertise, the USAF initiated discussions with Boeing about the F-15X project, later designated as the Advanced F-15 program. This initiative proposed developing a single-seat variant based on the F-15QA to replace the USAF’s F-15Cs/Ds. Boeing expanded the proposal to include both single- and two-seat variants (F-15CX and F-15EX, respectively), both sharing identical capabilities derived from the proven F-15E platform.
Ultimately, the USAF selected the two-seat F-15EX as its preferred solution. This strategic decision allowed the service to leverage existing F-15E production infrastructure, avoiding substantial non-recurring startup costs while enabling accelerated delivery timelines. Boeing secured the development contract for the F-15EX, which incorporated several groundbreaking enhancements, including a redesigned airframe structure rated for 20,000 flight hours, next-generation cockpit and flight control systems, and an advanced weapons carriage system capable of carrying up to 22 air-to-air missiles.
Design Features
The F-15EX retains the two-seat configuration of the F-15E while sharing approximately 70% commonality with earlier F-15C and F-15E Strike Eagle models. The aircraft incorporates numerous advanced systems within its highly digital avionics suite, including a Large Area Display glass cockpit, Joint Helmet Mounted Cueing System, and modern sensors.
The aircraft’s defensive systems revolve around the sophisticated AN/ALQ-250 EPAWSS, which integrates an all-aspect radar warning receiver, advanced threat geolocation capabilities, and AN/ALE-47 countermeasures dispenser. This avionics suite’s open systems architecture enables compatibility with planned future upgrades throughout the aircraft’s service life.
For sensor capabilities, the F-15EX features the cutting-edge APG-82(V)1 AESA radar providing extended-range multi-target tracking. The aircraft also incorporates the Lockheed Martin Legion Pod equipped with AN/ASG-34(V)1 IRST21 sensor, delivering long-range passive detection capability against airborne threats. These integrated systems dramatically enhance crew situational awareness and survivability, with the Weapons Systems Officer able to efficiently manage complex systems to support the pilot during demanding air superiority missions.
The F-15EX introduces digital fly-by-wire flight controls and is powered by two F110-GE-129 engines, each producing 29,500 pounds of thrust. This advanced propulsion system enables a top speed of Mach 2.5 at optimal altitudes while significantly improving overall maneuverability and handling characteristics.
With its exceptional payload capacity, the F-15EX can carry diverse weapons configurations, including AIM-120 AMRAAMs and AIM-9 Sidewinders for air-to-air engagements. Like its F-15E predecessor, it maintains full multirole capability with capacity for LANTIRN and Sniper XR targeting pods along with precision munitions including GBU-39 SDBs, JDAMs, AGM-88 HARMs, and AGM-158 JASSMs. Theoretically, the F-15EX could employ expanded racks and Conformal Fuel Tank (CFT) weapons stations to potentially carry 16 AIM-120s, 4 AIM-9s, and 2 AGM-88s simultaneously, though this configuration remains untested on operational F-15EX aircraft. These formidable capabilities, combined with its reinforced airframe structure, establish the F-15EX as the most capable strike fighter with primary air superiority mission capability.
While not designed to match fifth-generation fighter survivability against advanced threats, the F-15EX provides essential complementary capabilities to the F-35A fleet. The F-15EX Eagle II specializes in homeland defense missions, no-fly zone enforcement, and standoff weapons delivery in support of frontline stealth aircraft operations.
Production and Service Entry
The Department of Defense initiated the F-15EX program with an order for eight aircraft in July 2020, with deliveries scheduled across three years. The first F-15EX completed its maiden flight on February 2, 2021, at St. Louis Lambert International Airport during a tightly secured ceremony. This initial aircraft was transferred to Eglin Air Force Base, Florida, in March 2021 for testing, and on April 7, 2021, the Air Force officially designated the aircraft as “Eagle II.”
The first two production F-15EXs entered the USAF inventory and participated in critical weapons separation tests during Northern Edge and Combat Hammer exercises in May and August 2023. The third production aircraft incorporated enhanced communications equipment and a redesigned forward fuselage to meet specific USAF requirements, becoming the first F-15EX equipped with the complete EPAWSS system. Leveraging previous testing conducted on Saudi (F-15SA) and Qatari (F-15QA) variants, the F-15EX test program achieved significant progress with relatively modest time and resource investment. By August 2023, the aircraft had successfully completed weapons trials and mission systems testing.
Since 2020, the USAF has systematically planned to replace Air National Guard F-15C units with F-15EXs. The 142nd Wing of the Oregon Air National Guard made history as the first operational unit to receive the F-15EX Eagle II, with the initial combat-ready aircraft arriving at Portland Air National Guard Base on June 5, 2024. The USAF formally confirmed the F-15EX’s achievement of Initial Operational Capability on July 10, 2024. This milestone aircraft was the first of eighteen F-15EXs allocated to the 142nd Wing, and all others are manufactured at Boeing’s St. Louis production facility.
Current production F-15EXs are receiving the baseline EPAWSS configuration upon delivery. However, planned fleet numbers have been reduced from the original 144 aircraft to 98 due to evolving operational requirements and budget considerations.
As of June 2024, Boeing had delivered eight F-15EX aircraft (Lot 1A and 1B), with six allocated to developmental testing at Eglin AFB and two operational aircraft serving with the 142nd Wing of the Oregon ANG.
The January 2025 FY2024 Annual Report for Operational Test & Evaluation revealed a noteworthy update for the F-15EX aircraft, including completed cyber survivability testing on an F-15EX Lot 1B aircraft and ongoing development of assessment plans for Lot 2 aircraft. On March 17, 2025, Boeing announced the completion and successful first test flight of the ninth F-15EX (EX9) from Lot 2 production. This aircraft, currently in the delivery process to the USAF, will become the third F-15EX assigned to the 142nd Wing. Additional Lot 2 deliveries are scheduled throughout 2025 and will further strengthen the Air Force’s next-generation air superiority and homeland defense capabilities.
Looking toward future capabilities, Boeing is actively developing manned-unmanned teaming systems that will enable the Weapons Systems Officer to coordinate with loyal wingman drones. If this comes to reality, this technology would represent a significant evolution of air warfare, where unmanned systems will play increasingly vital roles in future operations.
