Why do dogs lick and bite the air

I think they do because of the bugs in the air or just because they r bored

It's a type of curiosity that dogs have with the world around them and the fact that they have a sense of hearing, taste, and smell a lot more acute than humans amplify the world around them.

I have seen dogs do this... but you do not want it to become excessive.Its only a problem if they become obsessed with things like this and then they will pick up another habit and another until they are a mess of nerves.