Ukraine’s shock drone strike on Russia’s strategic bomber fleet this week has generals and analysts taking a new look at threats to high-value United States aircraft at bases in the homeland and abroad – and the situation is worrisome.

Russia has hit Ukraine's second-largest city, Kharkiv, with a massive drone and bomber attack, killing four people and injuring nearly 60, officials say. Two people were also killed in Russian strikes on Kherson, in southern Ukraine, local authorities said.