What first came to mind was the B-52 Stratofortress, because of its name, size and cruising altitude, which as its name suggests is the stratosphere. It was commissioned in the late 40's and performed the majority of its duties in Vietnam, during the Operation Arclight carpet bombing and defoliation campaigns, though I am not sure what aircraft dropped the defoliants and napalm as the Stratofortress, or more frequently informally referred to as the BUFF, the "Big, Ugly, Fat Fucker," only dropped conventional munitions.
What other unreasonably large, well armed, and high flying airships have also been in use during military history, what events were they deployed to, and what were their primary functions? Also, any stories or tales about them could be fun to hear as well.
Here is the Wikipedia if people want to see some pictures of the B52 Stratofortress https://en.m.wikipedia.org/wiki/Boeing_B-52_Stratofortress
Though, obviously I link it only for pictures, not to suggest that this is a source or something with accurate information, it just has some good, easy to find pictures if you want to get a look at the aircraft, like a picture of it on the runway with all of its munitions laid out in front of it.