Boeing has delivered another two F-15EX Eagle IIs to the U.S. Air Force, a year later than originally hoped. Manufacturing-related issues were the primary driver behind the delays.

A spokesperson for Boeing confirmed to The War Zone that the Air Force's third and fourth F-15EXs, also known as EX3 and EX4, were delivered to Eglin Air Force Base in Florida today. Air Force pilots and weapon system officers (WSO) had conducted pre-delivery checkout flights on these jets earlier this month. Previous reports have also said the EX3 is the first Eagle II to be produced in the final production configuration, which includes the AN/ALQ-250 Eagle Passive Warning Survivability System (EPAWSS) electronic warfare suite.

Boeing says it has delivered the second pair of F-15EX Eagle II fighters to the U.S. Air Force after a year of delays.

EX3 and EX4 have now joined the Air Force's initial pair of F-15EXs, which were delivered between March and April 2021, at Eglin. All four jets are part of an Eagle II test force.

Boeing's spokesperson further told The War Zone today that the company hopes to deliver the next two F-15EXs to the Air Force before the end of the year. These jets will also be assigned to the test unit at Eglin.

Another two F-15EXs are currently under construction for the Air Force and are set to join the Oregon Air National Guard 142nd Fighter Wing early next year. The 142nd is set to be the first operational unit to fly the Eagle II. The Air Force currently plans to buy a total of 104 F-15EXs.

Boeing had originally expected to deliver EX3 in December 2022, already more than a year after the Air Force received its first pair of F-15EXs. The delivery timeline for EX3 was subsequently pushed back multiple times this year. The jet only flew for the first time in October.

A report that the U.S. Government Accountability Office (GAO), a congressional watchdog, published earlier this year blamed the F-15EX delivery delays on manufacturing problems at Boeing and with third-party suppliers, as well as budgetary issues stemming from fluctuations in the planned Eagle II fleet size. Last year, the Air Force moved to truncate its expected purchases of F-15EX from at least 144 to just 80, before increasing that figure to 104.

It is important to note that the delays have not yet led to a formal breach of the F-15EX program's schedule. If the Air Force receives the next four Eagle IIs between now and July of next year, it should be able to meet the official requirements to declare initial operational capability (IOC) with the type.

At the same time, the saga of delivering the second pair of F-15EXs to the Air Force, together with the fact that the service will be able to declare IOC with just two jets assigned to an operational unit, speak volumes about the now long-standing questions surrounding the plans for the Eagle II fleet. By comparison, the Air Force had 15 jets assigned to its first operational F-35A squadron when it declared IOC for that type in 2016.

As of December 2022, what it would take to achieve Full Operational Capability (FOC) with the F-15EX is just 44 jets, "along with delivery of training equipment and material, support equipment, spares, and technical data," according to a now declassified Pentagon Selected Acquisition Report (SAR). The 2022 SAR said that the goal then was for that milestone to be achieved in September 2026, but that the official deadline was July 2027.

As it stands now, the Air Force has officially announced plans to establish three operational squadrons of F-15EXs, one each within the Oregon, California, and Louisiana Air National Guards, where they will replace aging F-15C/D Eagle fighters. The service has also formally axed plans to establish a dedicated Eagle II schoolhouse unit within the Oregon Air National Guard in favor of blending together the F-15EX and F-15E Strike Eagle training pipelines. The Oregon Air National Guard's existing F-15C/D schoolhouse squadron is now set to transform into an F-35A training unit.

A report just this week from Japan's Nikkei Asia news magazine said that the service is planning to forward deploy two additional squadrons of Eagle IIs to Kadena Air Base in that country. You can read more about what this might mean here. This is something The War Zone has speculated could occur in the past, especially following the announcement last year that the Air Force was shuttering a pair of F-15C/D squadrons at Kadena without any immediate plans for permanent replacements. This would also round out the assignment of all 104 F-15EXs the Air Force presently plans to acquire.

As The War Zone explored in great detail earlier this year, there are significant questions about whether or not a fleet of just over 100 F-15EXs will allow the Air Force to get the most out of the type, or even what its commanders say they want from the jets. Though the main role of the Eagle II will be air defense, including of the U.S. homeland, it presents an ideal launch platform for outsized munitions, including hypersonic weapons, as well as other large stores. It could also provide new advanced electronic warfare capabilities.

The Eagle II, with its two-person cockpit, is particularly well positioned to act as an airborne controller for the hundreds (or more likely thousands) of future Collaborative Combat Aircraft (CCA) that the service plans to acquire in the coming years. Air Force Gen. Kenneth Wilsbach, head of U.S. Pacific Air Forces (PACAF), who had advocated in the past for deploying F-15EXs to Kadena and is a big proponent of the CCA program, has said he expects collaborative drones to be based there in future, as well.

There, of course, always remains the possibility that the Air Force could decide to further increase the size of its F-15EX fleet down the line. Boeing is already looking at foreign sales of Eagle IIs, as well. Earlier this year, Indonesia formally committed to buying 24 F-15IND jets, which will be derived from the EX, and Poland has also expressed interest in the Eagle II.

Whatever the future might hold for the Air Force's truncated F-15EX fleet, deliveries of additional Eagle IIs do at least now seem to be proceeding.