"Air Master" is a satire and since a lot of folks don't "get" satire they gave it a "1". And those folks, by their reasoning, would be correct:
- the story is non-existent
- the art is all over the place
- the animation sucks
- the character design, well, the lead (except in flashback) is a hulking sort of Amazon; there's a "psycho supporter" lesbian who wears a bra with a cup size so large only Dr. Seuss could come up with a letter designation for it; a dwarfish creature that appears to have escaped from "Spirited Away" or, more likely, was exiled; and there's also "those two characters who are always hanging around the lead character"; and then there are the other characters who show up, disappear for no apparent reason and then resurface several episodes later for the same no apparent reason.
CHARACTER DEVELOPMENT? WE DON'T NEED NO STINKIN' CHARACTER DEVELOPMENT!
So it's understandable that the folks who watched "Air Master" assuming it was about an outsider girl "finding her way to acceptance by being the bad ass-est fighter on the street" would be upset and think it deserves a "1". It's also understandable that they missed the point entirely; they were clearly watching the wrong anime.
"Air Master" works on two levels: it's a satire but, also, in the grand tradition of "Usagi-chan de Cue!!", it's superbly silly. There is about one really decently animated fight sequence per episode along with quite a few good jokes including satirical comments about anime in general (note "the two characters who are always hanging around the lead character").
That's it nothing more, nothing less. "Air Master" is a fairly sophisticated satire presented as a silly action anime.