So during the cold war, the US was like "Man, what if Russia nuked all of our command centers and no one was left to launch our nukes! A missile could be here in 15 minutes and we wouldn't be able to react!"
And the solution to this was to have a plane in the air at all times that could command all nuclear forces from the sky. Wikipedia
tells us "Looking Glass aircraft were airborne 24 hours a day for over 29 years, until July 24, 1990, when "The Glass" ceased continuous airborne alert, but remained on ground or airborne alert 24 hours a day"
Which is a long time to always keep planes up in the sky
But this is my favorite part
"The Looking Glass pilot and co-pilot were both required to wear an eye patch, retrieved from their Emergency War Order (EWO) kit. In the event of a surprise blinding flash from a nuclear detonation, the eye patch would prevent blindness in the covered eye, thus enabling them to see in at least one eye and continue flying"