Key Points – President Trump’s May 15th suggestion in Qatar of developing an “F-55″—a twin-engine “super upgrade” of the single-engine F-35 because he “doesn’t like single engines”—is as an overly simplistic and impractical concept.
-Aircraft design necessitates complex trade-offs between weight, thrust, stealth, and cost; simply adding a second engine to the F-35 would require a complete airframe redesign, effectively creating a new, costly aircraft and negating F-35 commonality benefits.
-This idea, alongside concurrent talk of an “F-22 Super” and the existing F-47 NGAD program, raises serious questions about feasibility, funding, and strategic coherence in future US fighter development.
Trump’s F-55 Fighter Idea Isn’t Based on Reality
Whatever the problems of the F-35 fighter– and there are many – one thing seems clear: adding a second engine won’t fix them.
Which is why President Donald Trump’s talk of a twin-engine version of the F-35 – which he dubbed the F-55 is so bizarre.
“We’re doing an upgrade,” Trump said during a speech in Qatar. “A simple upgrade, but we’re also doing an F-55, I’m going to call it an F-55, and that’s going to be a substantial upgrade, but it’s going to be also with two engines, because the F-35 has a single engine, I don’t like single engines.”
Whether the laws of physics and aerodynamics care about Trump’s preferences isn’t the question. Nor is it merits of single-engine versus twin-engine fighters. Both types have advantages and drawbacks: single-engine fighters are smaller, cheaper and more maneuverable. while twin-engine designs are heavier but can carry more weapons and fuel, enjoy longer range and in theory can keep flying if one engine goes out.
Comparing a twin-engine 16-ton F-15 to a single-engine 10-ton F-16 is pointless: they are optimized for different missions and reflect different philosophies of airpower.
The Single-Engine F-35
It is true that the F-35 is something of a minority in opting for one engine. Many contemporary fighters have two engines, including the U.S. F-18 E/F Super Hornet, France’s Rafale, the Eurofighter Typhoon, Russia’s Su-30 and China’s J-20. But there are also plenty of single-engine designs, including the F-16, Sweden’s Gripen, and China’s J-10.
As might be expected from a politician and businessman who believes that more is better, it is not surprising that Trump believes that more engines makes for a better fighter. It’s the level of thinking satirized in George Orwell’s classic “Animal Farm,” where the animals rebelling against their human masters are taught to repeat “Four legs good, two legs bad.”
How many engines should the F-35 have? Exactly the number that it needs. Aircraft, like tanks and warships, are a balance of competing factors such as weight, thrust requirements, maneuverability and payload.
The F-35 was originally conceived more than 30 years ago as a stealthy strike aircraft, not an air superiority fighter like the F-15 or F-22. There is ample reason to question aspects of the F-35’s philosophy, not least the decision had to be made in order to create a common design that could serve as an Air Force land-based fighter, a Navy carrier-based fighter, and a Marine Corps vertical-takeoff jet. Given these constraints, a second engine would have added size, weight and complicated an already overcomplicated aircraft.
Second Engine Time?
What would an F-35 be with a second engine?
The answer is that it would not be an F-35.
The airframe would have to redesigned to incorporate a larger powerplant while still maintaining a stealthy shape. And would this F-55 be a common aircraft like its predecessor? Developing the original F-35 was hard enough when accommodating the differing needs of the Air Force, Navy and Marine Corps, and especially the Marine requirement for a vertical-takeoff aircraft. The thought of having to undergo this process again – this time with two engines – would make any aircraft designer blanch.
A U.S. Air Force F-35 Lightning II taxis during a cross-servicing event at NATO Allied Air Command’s Ramstein Flag 2025 exercise April 4, 2025. Successful cross-servicing at RAFL25 is an example of the importance of integrated logistics and maintenance training that enhances U.S. warfighting readiness by strengthening United States Air Forces in Europe – Air Forces Africa’s ability to deploy, sustain, and project fifth-generation capabilities across the European theater. (Royal Netherlands photo by Sgt. Maj. Jan Dijkstra)
Naturally, Trump wants a discount on the super F-35. “If we get the right price, we have to get the right price, that will be two engines, and a super upgrade on the F-35,” he said. Given the history of U.S. fighter projects, a F-55 that comes in on time and under budget would be a miracle.
As if revamping what is shaping up to be the primary fighter of the U.S. and Europe wasn’t enough, Trump also wants to redesign the F-22, which first flew in 1997. “I think the most beautiful fighter jet in the world is the F-22, but we’re going to do an F-22 Super, and it will be a very modern version of the F-22 fighter jet,” he said.
In fact, the Air Force only bought 187 F-22s, which ended up costing around $350 million apiece (the F-35 costs less than $100 million each). Considering that the original F-22 is almost 30 years old, the redesign would likely be substantial enough that the result would be a totally new aircraft. Indeed, Trump has also boasted that America will build the F-47, a next-generation fighter that sounds a lot like the F-22 (including a price tag already estimated at $300 million per aircraft).
Whether all these fighter projects will come to fruition is unlikely. Budget constraints, plus multiple changes of occupant in the White House, will inevitably change priorities. How many engines a fighter has will be the least of these issues.
About the Author: Michael Peck
Michael Peck is a defense writer whose work has appeared in Business Insider, Forbes, Defense News, Foreign Policy magazine, and other publications. He holds an MA in political science from Rutgers Univ. Follow him on Twitter and LinkedIn
