A burning oil terminal following an air attack in St. Petersburg on Oct. 18. | AFP-JIJI

When he started flying unmanned aircraft in combat, “Ray” was flying some of Ukraine’s earliest midrange strike drones, on missions of about 100 kilometers with a warhead about the weight of a bowling ball.

Now many of the weapons he works with are small, cheap cruise missiles that fly deep into Russia and Russian-occupied Ukraine, hitting everything from air defense systems to natural gas terminals and oil refineries.

The transformation in striking power is down to evolving Ukrainian manufacturing prowess — but also complex mission planning using detailed maps, satellite photos from Western partners that show Russian air defenses, a robust intelligence network and even energy industry veterans, whose expertise identifies weak spots in production facilities.…