It was a very good Lear

Sinatra at home with a replica of the Christina II on the piano. (source)
Private Air Daily has a fascinating article about the fate of the Learjet Sinatra owned for a couple of years during the mid-60's, the Christina II. If those cockpit walls could talk! From the article:

If ever a plane played among the stars, it was N175FS. From June 1965 until he sold it two years later, Frank Sinatra and his famous friends logged more than 1,500 hours on the small, powerful early business jet. Sinatra routinely used it to shuttle the Rat Pack from Los Angeles to Las Vegas and his home in Palm Springs. He wooed Mia Farrow in it, and intimidated Michael Caine, then dating his daughter Nancy, in the back.

Celebrity private-plane culture was practically invented on it: At a time when few had their own private jets, when most Americans had never seen a private jet, Sinatra and his plane were like Hollywood's version of the first kid in class with a car. Dean Martin borrowed it to fly to movie sets. Marlon Brando and Sammy Davis Jr. took it to Mississippi to meet Martin Luther King Jr. for a civil-rights rally. Elvis Presley eloped with Priscilla Beaulieu aboard it.

With Dino (note the color - orange was Sinatra's favorite color)
Check it out. There's much more to it, complete with a cool slideshow.

Related post: "Hangin' out with Frank"