Ukraine is developing new technology to blast Russian drones out of the sky for a fraction of the cost of American-made weapons used to counter Moscow’s massive escalation in drone warfare this summer, and The Post got a chance to check out two production companies leading the way. Drone-interceptor missiles and interceptor drones are the latest advancements to protect Ukrainian skies — and may help keep safe other countries, including the US, in a future modern war. A single, highly advanced interceptor missile or rocket can cost as much as $100,000 to $250,000, such as those used by the US’ Patriot air-defense systems, according to Pentagon data.