I keep wondering if this is a preview of the future. If I were a nation state looking to initiate hostilities, how "easy" it would be to have a handful of kamikaze drones discretely built and distributed around juicy targets.
Radar, AA, expensive jets, core infrastructure. All attacked as part of an opening salvo which could cripple the enemy's forces on the first day.
The US learnt this lesson over 80 years ago with the simultaneous attacks on Pearl Harbour, Guam, Wake, Midway and the Philippines.
The difference is these days satellite surveillance makes it harder to secretly move military forces into place. Drone carrying cargo ships is the biggest risk.