In 1989, the Chinese Chengdu Aerospace Corporation unveiled a major upgrade for its locally-made F-7 jet fighter, a licensed copy of the classic Soviet MiG-21. The new F-7 variant moved the engine air intake from the nose tip to the sides of the fuselage, making room in the nose for a more powerful radar. Twenty-one years later, this upgrade—now named JF-17 Thunder—is flying combat missions with the Pakistani air force, so far its sole user. Further enhanced with a new wing, a cutting-edge intake design and a new, more powerful engine, the JF-17 is Pakistan’s most important front-line fighter—and a...