Storm elementals are pretty much perky air elementals. They may be slower, but they pack quite a bit of zap, especially when you get to the bigger ones of the bunch. The little fellas can be pretty useful as a summoned ally, since their attacks actually deal sonic and electric damage at the same time. If one bit of hurt can't get through, the other one probably will.
They may well be the reason why airplanes and such never quite took off in fantasy worlds. Magical airships maybe have some kinda magical protection against storm elementals coming along and puncturing their balloons.
I like to think of these guys hanging around blue dragons, thunderbirds and the other big electric beasties of the sky, just hanging around them like remora on a shark.