Ironbending

I'm not even sure what an Airbender is, or how one would notice if the air was bent without special skills or equipment. If, however, you pick up a straight bar from the middle, it will bend down at the ends. Unladen, this bend will not be detectable without the aforementioned skills and equipment.

Applying a substantial load, however, will make it apparent without the fancy shit. You just have to be able to do it.

( Pic & video behind the cut )