Putin's invasion. Tanks were not the answer and Russia failed miserably. Drones however readily give Ukraine the means to provide opportunities for innovation in weapon design at a fraction of the cost. Perhaps more importantly drones have also given Ukraine independence from unreliable support,
particularly from the US. Consider the dragging of feet by the Biden administration at the beginning of the war, so much could have been achieved were it not for the US indecisiveness in the use of long range weapons. Now consider the Trump administration and where the war in Ukraine would be
without the ability to design and build drones that have given them the independence to fight on their terms and not Putin's or indeed Trump's! If it weren't for drones, the nation of Ukraine and its wonderfully brave people would be all but over. In a nutshell, there is not one answer that fits all