U.S. President Donald Trump’s proposal for a new twin-engine iteration of Lockheed Martin’s F-35 fighter jet, dubbed the “F-55,” faces significant challenges due to steep costs and complex engineering demands, according to sources familiar with the matter.
In a speech in Doha last month, Trump described the F-55 as featuring “two engines and a super upgrade on the F-35,” while adding a crucial caveat: “if we get the right price.” However, insiders reveal that Trump was not presented with any concrete twin-engine redesign of the F-35 prior to his remarks.
Developing such a jet would require a comprehensive redesign of the existing airframe, involving billions of dollars in expenditure and multiple years of development. Lockheed Martin had briefed Trump on an F-35 upgrade that included a single advanced engine, a redesigned nose and forward fuselage, and a new sensor suite—but not a twin-engine variant, the sources said.
The mention of the “F-55” designation and the twin-engine configuration caught officials and defense industry experts off guard. Trump has expressed a preference for twin engines, citing enhanced safety in the event of an engine failure.
Lockheed Martin is reportedly exploring two new fighter jet variants amid mounting global competition in military aviation. China is accelerating development of its J-36 and J-50 stealth fighters, while Russia presses forward with its Su-57 despite economic challenges.
Following Trump’s announcement, Lockheed responded cautiously, stating, “We thank President Trump for his support of the F-35 and F-22 and will continue to work closely with the Administration to realize its vision for air dominance.”
Wall Street analysts tracking Lockheed Martin’s next-generation fighter efforts interpreted Trump’s comments as a call for the Department of Defense to consider a twin-engine version of the F-35 “if we get the right price,” according to a TD Cowen note.
Industry experts warn that switching the F-55 to a twin-engine layout would trigger a costly and prolonged redesign of the F-35’s airframe. While this could boost the jet’s speed and safety, it would likely delay production by several years.
Lockheed CEO James Taiclet has indicated the company is investigating a “fifth-generation-plus” fighter concept that leverages technologies developed for the company’s unsuccessful F-47 bid. These advancements aim to transform the existing F-35 platform into a more capable aircraft, described by Taiclet as turning the jet’s “chassis into a Ferrari,” delivering 80% of next-generation performance at roughly half the cost.
Meanwhile, Boeing secured the contract for the Next Generation Air Dominance (NGAD) program with its F-47 fighter, slated to become America’s first sixth-generation fighter and replace the F-22 Raptor.
Because Lockheed lost the NGAD competition, it now faces pressure to maximize its existing production capabilities. The company reportedly has production capacity ready to ramp up, and Trump was informed that Lockheed is further along in its development than he had realized.
The announcement of the F-55 concept raises critical questions about its integration into the Pentagon’s current defense procurement and budgetary frameworks. The Department of Defense is already juggling multiple high-cost aviation programs, including the ongoing F-35 production, the F-47 development, and the Navy’s next-generation carrier-based fighter project, the F/A-XX.
For Lockheed Martin, the F-55 represents a pivotal opportunity to retain its foothold in the high-end fighter market after setbacks in next-generation competitions. The forthcoming Boeing NGAD is expected to surpass the F-22’s capabilities, and the F-55, if realized, would pose a formidable challenge as a cutting-edge fighter jet.