Ever since word first broke last summer that the U.S. Air Force was considering (at the Pentagon’s direction) the idea of adding a dozen or so new F-15s to their stable as part of their 2020 budget proposal, outlets have been clamoring to find ways to pit the new F-15X against America’s premier stealth fighter, the F-35.

Fans of the fifth-generation fighter of the future have repeatedly argued that devoting funding to an upgraded version of an older jet is a fool’s errand, suggesting that those funds should instead be used to expand deliveries of the F-35. Of course, these arguments consistently ignore statements made by both Lockheed Martin and Pentagon officials, which have made clear the F-15X funding will have nothing to do with the F-35. Defense pundits (and some officials) seem so eager to compare these two platforms that they forget they were actually built for very different jobs. Jeeps and Ferraris are both passenger vehicles, after all, but some situations are just better suited for one over the other.


Such would be the case for the F-15X, which, instead of replacing F-35s, would actually replace 30+-year-old F-15s that America intends to keep in the skies for decades to come. The new (old) fighters would boast more than five billion dollars’ worth of research and development compared to their aging kin, thanks to Boeing’s continued development and production of the airframe for sales to allies like Saudi Arabia and Qatar. The new F-15X would offer significant savings over older F-15s in terms of operating costs while bringing a far more advanced suite of onboard systems into the mix thanks to 30 years of continued advancements.

The F-15, including the new F-15X variant, are purpose-built air-superiority fighters with the singular purpose of hunting down and engaging enemy aircraft. The F-35 Joint Strike Fighter, for all its incredible capabilities, was truly designed for air-to-ground engagements. That’s not to say it couldn’t cause some real trouble for enemy aircraft, but it’s important to note the differences in what these jets were built to do, as well as the difference in the types of operations with which they would typically be tasked. The F-22 Raptor, not the F-35, is considered America’s premier air-superiority fighter; its mission would have far more overlap with the F-15X.