What Happened to Lockheed Martin F-35 Lightning II?

The Lockheed Martin F-35 Lightning II program, which commenced in November 1996, has evolved into the most ambitious and expensive defense initiative in history, with a projected acquisition and sustainment cost exceeding $2 trillion over its 77-year lifespan through 2088. Designed as a versatile fifth-generation multirole combat aircraft, the F-35 aims to provide air superiority, strike capabilities, electronic warfare, and intelligence, surveillance, and reconnaissance functions for the U.S. Air Force, Navy, and Marine Corps, as well as numerous international partners.

The program's immense cost and complexity are primarily driven by its state-of-the-art stealth technology, advanced sensor fusion, and the requirement to replace a multitude of legacy aircraft across different services and allied nations. The F-35's ability to integrate diverse data streams into a single, fused tactical picture for the pilot is a core strength, enabling it to operate effectively in contested airspace. Key turning points include Lockheed Martin's X-35 winning the Joint Strike Fighter competition in 2001, the F-35A's first flight in 2006, and its entry into U.S. service between 2015 and 2019. The aircraft first saw combat in 2018, with Israeli F-35s in Syria and U.S. Marine Corps F-35Bs in Afghanistan.

However, the F-35 program has been consistently plagued by challenges, particularly concerning its Block 4 modernization and Technology Refresh 3 (TR-3) upgrades. TR-3, the computing and memory foundation for Block 4, experienced significant hardware and software delays, leading to a halt in aircraft deliveries from July 2023 to July 2024. Combat-capable TR-3 jets only began reaching squadrons in 2026, approximately three years late. The Block 4 upgrade, intended to add new weapons, electronic warfare improvements, and radar enhancements, is now expected to be completed by 2031 at the earliest, five years beyond its original schedule, and has seen its estimated cost increase by at least $6 billion.

These delays and technical issues have had tangible consequences for fleet readiness. The Government Accountability Office (GAO) reported in June 2026 that the fleet-wide mission-capable rate declined from 67% in fiscal 2021 to 44% in fiscal 2025, with the full mission-capable rate dropping to 25%. Sustainment has emerged as a major problem, with the current support structure struggling to keep pace with the growing global fleet of over 1,300 aircraft. Furthermore, the F135 engine's power and cooling margin are nearly exhausted, necessitating an Engine Core Upgrade (ECU) and a separate power-and-thermal-management upgrade, with the ECU's critical design review slated for August 2026.

As of July 31, 2026, the F-35 remains a cornerstone of U.S. and allied air power, with Lockheed Martin expecting to sustain an annual production rate of 156 aircraft due to ongoing demand. Recent developments include a nearly $1.3 billion contract awarded to Pratt & Whitney for F135 engine spare parts to bolster global sustainment and the U.S. Air Force's expansion of Blade Diagnostics' SmartBlend engine maintenance platform for F-35 engines. Operationally, F-35s participated in Exercise Pitch Black 2026 in Australia and U.S. F-35 squadrons were certified for combat operations during Combat Archer UK 2026. However, geopolitical tensions saw an F-35 make an emergency landing after a combat mission over Iran in March 2026, with conflicting reports on whether it was hit. The U.S. also significantly reduced its planned F-35 procurements for Fiscal Year 2026 by 45%, acquiring only 47 aircraft, partly due to funding shifts towards sixth-generation fighter development. Turkey's re-entry into the program remains blocked due to its S-400 missile system acquisition.