Michael Muhney Firing -- Fans Protest By Getting Super High

Fans of fired soap star Michael Muhney are taking to the air -- protesting 1,000 feet in the sky -- to make sure CBS honchos know they're really pissed off.

TMZ broke the story ... die-hard fans wanted to make a strong statement of support for Muhney -- who was fired from "The Young & The Restless" for allegedly groping the breasts of his 20-year-old co-star Hunter King.

So ... they plunked down $785 for an aerial banner flown over the CBS studios in L.A. where the show is filmed. The banner screams: TEAM MUHNEY SUPPORTS MICHAEL MUHNEY.