Boeing’s entry in the Joint Strike Fighter competition was called the X-32.
The Boeing X-32 was a demonstrator aircraft developed for the United States Department of Defense’s Joint Strike Fighter program. Boeing proposed a common basic design that could be adapted for conventional takeoff, carrier operations, and short takeoff and vertical landing.
Two X-32 prototypes were built and tested in the early 2000s. The aircraft had a distinctive large chin-mounted air intake and was designed around a commonality goal intended to reduce development and operating costs across different versions.
The competing Lockheed Martin X-35 won the program in 2001 and became the basis for the F-35 Lightning II. The X-32 therefore should not be confused with the X-35, even though both were designed for the same competition.