free as air/as a bird

(as) free as (the) air

1. Unencumbered; without constraints or restrictions. The phrase means the same as "free," but with more emphasis. I'm as free as air this Friday! Do you want to meet for dinner? A: "Are you still with Brian?" B: "Nope, I'm single now—free as the air!"
2. Happy and untroubled. Betty must be free as air because I never see her in a bad mood.
See also: air, free

(as) free as a bird

1. Unencumbered; not restrained by anything. The phrase means the same as "free," but with more emphasis. I'm as free as a bird this Friday! Do you want to meet for dinner? She's single now—free as a bird!
2. Happy and untroubled. Betty must be free as a bird because I never see her in a bad mood.
See also: bird, free
Farlex Dictionary of Idioms.

*free as a bird

 and *free as (the) air
Cliché carefree; completely free and unhindered. (*Also: as ~.) Jane is always happy and free as a bird. The convict escaped from jail and was as free as a bird for two days. No, I'm not married. I don't even have a girlfriend. I'm free as the air.
See also: bird, free
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

free as a bird

At liberty, without obligations, as in Can you join us tonight?-Yes, I'm free as a bird, or He's free as a bird-he can travel wherever he chooses. [c. 1700]. Also see footloose and fancy-free.
See also: bird, free
The American Heritage® Dictionary of Idioms by Christine Ammer.

free as a bird

BRITISH, AMERICAN or

free as the air

BRITISH
If someone is free as a bird or free as the air, they are completely free and have no worries or troubles. I have been island-hopping in the Pacific for the past two and a half years, free as a bird. They think of us as favoured beings, going where we like, working when we feel like it, free as the air. Note: You can also say that someone is free as air. Our children play around in the August heatwaves, free as air and enjoying independence.
See also: bird, free
Collins COBUILD Idioms Dictionary, 3rd ed.

(as) free as (the) ˈair/as a ˈbird

completely free: You can’t imagine what it’s like to feel as free as the air. Nobody who hasn’t been in prison can imagine it.
See also: air, bird, free
Farlex Partner Idioms Dictionary

free as a bird

Totally at liberty. Being able to fly about at will has long seemed to be the epitome of freedom. The simile here dates back at least to the seventeenth century, when “as free as a bird in ayre” appeared in the Somers Tracts (1635).
See also: bird, free
The Dictionary of Clichés by Christine Ammer
See also:
  • (as) free as (the) air
  • (as) free as a bird
  • free as a bird
  • free lunch
  • a free lunch
  • the only free cheese is in the mousetrap
  • You don't get for nothing
  • Es
  • (there) ain't no free lunch(es)
  • there's no such thing as a free lunch