KUJAWY-POMERANIA PROVINCE, Poland — Olexi Kroshchenko, a clean-cut Ukrainian helicopter pilot, stood elbow-to-elbow with Chase Bailey, a bearded Las Vegas hipster, and learned how to fly drones in war zones.
Within days, Kroshchenko hoped, some of the 10 specialized quadcopters donated by an American manufacturer would be angling into the treacherous gaps of bombed-out apartments and high-rises, giving Ukrainian rescuers a better chance to reach victims.
“A little more throttle,” said Bailey, gently touching the joystick controller. “Watch the screen, not the drone.”
“Da, yes,” said Kroshchenko, 25, as he mastered the subtle pitch and yaw of a device designed — with laser guidance, night-vision and a concrete-penetrating signal — to operate in the kind of grisly rubble being created daily by Russian missiles and shells.
Nearby, two others — Ukrainian military officers who had traveled secretly into Poland — were practicing another wartime application: using the drones to…