Oprah Winfrey. (AP file)

Oprah Winfrey is facing a lawsuit from a flight attendant over allegations of a sky-high tryst on board the media mogul's private jet.

Corrine Gehrls filed suit on Friday claiming she was fired from her job after she was accused of engaging in "inappropriate intimate behaviour" with a pilot during a flight as Winfrey slept elsewhere in the cabin.

Gehrls, who worked on Winfrey's private plane until July, alleges two other flight attendants hatched a plot to get her dismissed - accusing them of lying to Winfrey about the alleged onboard act.

She was subsequently fired along with Chief Pilot Terry Pansing.

Gehrls has filed suit against the star's Harpo company, as well the two other members of the flight crew - named as Myron Gooch and Kirby Bumpus, who is the daughter of Winfrey's best friend Gayle King.

The legal papers state, "Gooch and Bumpus falsely told Winfrey and Harpo that on the June 14, 2009 Harpo flight... Pansing and Gehrls had been observed having inappropriate intimate conduct outside the cockpit of the plane."

Gehrls is asking for damages in excess of $75,000, according to TMZ.com.