Is It Hair Brained or Hare Brained?

The spellings hare-brained and hair-brained are both accepted. (The hyphen is preferred in Canadian spelling, but the terms may also be written without it.)

Is it air brained or hair brained?

The spelling harebrained is most common. The spelling hair-brained is also frequently used, but some people consider it to be incorrect.

Where does the expression hare brained come from?

The 16th century harebrained came from the earlier harebrain, "giddy or reckless person," from the common impression of a rabbit or a hare as being nervous and skittish.