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.

The covert operation was described as one for the “history books” by Ukraine’s president. According to Ukrainian officials, nearly a third of Moscow’s strategic bomber fleet was destroyed or damaged with cheaply made drones sneaked into Russian territory in the span of a few hours on Sunday.

Drones are “ubiquitous, because they are quite useful, and they're demonstrating that every day in Ukraine,” one analyst told NBC News.

Russia is vowing to repair the planes that were seen heavily damaged by Ukraine over the weekend in a massive drone attack across multiple airfields.

Ukraine's overnight drone strikes have forced a temporary suspension of flights in all airports serving Moscow and the country's second-largest city St. Petersburg, but caused no damage, Russian officials reported on Tuesday.