Posted for potential spoilers.

I just saw the blimp in the sky a while ago, I have not actively gone searching for the Brotherhood yet.

While questing for the minutemen I came across two vertiberds, one of which was manned by the gunner gang. After cutting them down, I noticed the Brotherhood themselves began firing at me. Some of them were easy enough until two power armored knights cut ME down, forcing me to reload.

I hadn't met them yet. Are they supposed to be shooting at me? Or are they mad that I blew up two of their vertibirds?

If you didnt officially meet them yet, they probably open fire, would make sense to me. Not sure tho if maybe they would have been "friendly" if you met them outside of a firefight with 3 parties...

This whole who is good/bad from a range is too hard for me....RIP 3 Diamond City quards I killed on my first trip to the city

They did the same to me, guess they didn't like me single handedly wiping out everyone on their command ship, at the airfield, and the police station as soon as I heard their evil plan of genocide, I only felt bad when the little children ran from me, luckaly they dissapear when you do the quest to destroy their airship.

The Brotherhood was pretty brusk and unpleasant in FO3 till you got to know them anyway, not the easiest faction to get to know but they seem to be worse here.

Yea, I don't really plan on allying with them - though the one guy I was shooting at seemed to take absolutely no damage so I don't look forward to shooting more power armored folk.

With high level perks they take 2 shots - both to the head. One pops their helmet off and the other finishes them.