Drones have defined the war in Ukraine, with Russian and Ukrainian forces adapting to challenges in real time.Paula Bronstein/Getty ImagesDrones have seen a variety of functions in the Ukraine war on both sides.Reconnaissance drones gather information, while one-way attack systems strike tanks and troops.The drone war in Ukraine has implications for the US and other militaries looking at the future of war.In the Ukraine war, drones are causing all sorts of mayhem in the air, on the ground, and at sea.The drones being used in this conflict gather intel, provide targeting data, cripple ships and tanks, and even engage in drone-on-drone combat, and there is much the US and other militaries can learn from this fight about what future warfare will look like.In this war, an odd combination of World War I-style combat and modern technological innovations, drones have dramatically changed how soldiers fight and survey the battlefield.