KYIV, Ukraine—Ukraine’s unprecedented drone strikes on Russian air force bases weaken Moscow’s ability to wage war on its smaller neighbor and undermine its capacity to threaten more distant rivals such as the U.S.—a shift with potentially far-reaching geostrategic implications.

A sizable portion of the fleet Moscow uses to launch guided-missile attacks on Ukraine—and would rely on to strike adversaries in the event of a nuclear war—was damaged or destroyed in the coordinated attacks.