Seaming Pliers
I own HVAC, Avery (vice-grip style), and Cleaveland.
I prefer the Cleaveland and use them most of the time, but I also use the Avery in some areas since the shape is different.
HVAC stayed in the toolbox with my other HVAC tools once I tried them on some scrap...Jsharkey is right-they form too sharp a bend for aircraft use.
Mike