Forgot firmware password!

The only way to remove a firmware password on an Air is to have Apple do it, preferably at an Apple Store.

 

Is that true of the Retina MBP as well?

 

Yes. It is true for ever Mac made in and after 2010.

 

Yes.

MacBook Air (Late 2010) and later, MacBook Pro (Early 2011) and later, iMac (Mid 2011) and later, Mac mini (Mid 2011): Recovering a lost firmware password