Nothing except existing anti-drone measures around airports, e.g. radar, jammers, anti-drone drones, and eagles (https://www.bbc.com/news/av/world-europe-357508

Nothing except existing anti-drone measures around airports, e.g. radar, jammers, anti-drone drones, and eagles (https://www.bbc.com/news/av/world-europe-35750816 https://www.bbc.com/news/av/world-europe-35750816). What I'm saying is that a lot of infrastructure is very vulnerable if there is someone who wants to cause damage. Hand grenades or improvised explosives on commercially available or even home-built drones can cause a lot of havoc, assuming you have the operators and they can avoid being tracked down. The Russian invasion of Ukraine shows the efficiency of that, at this point there must have been hundreds of thousands of drones been used to great (and financially asynchronous) effects, on both sides. What ends up in the news and social media is likely just the tip of the iceberg.