You can probably find some examples of American flags on TTB labels. But TTB usually does not allow it, and for that reason you won’t find one on this label.
Manchester Brewing explains:
The feds forced us to remove part of the American flag, and replace the stars with a hammer and sickle. It’s the law, doesn’t have to make any sense. Originally, the Kombat ale was a Special Bitter, but it’s moved a bit beyond that.
A better view of the modified flag is here. Is it any wonder that TTB rejected a bunch of Manchester’s labels? Manchester goes on to explain:
Smacked Down by The Man! The TTB rejected all of our labels! One had a flag over the capitol; it was an American flag but that’s not allowed — so we put a Hammer and Sickle where the stars go, and that’s ok. Also, we used OMFG! on another label, and the government decided that was obscene, even though we protested that it meant Oh My Fairy Godmother and told them we were sticking to that story. So now it says “Censored” over the OMFG, and people tell me they find that funnier.
Why the tank?