I was in this boat/plane in November 2010 - it's tided up in a canal behind 17th St in Fort Lauderdale. It doesn't look as tidy now on the outside as in this pic, but the interior is immaculate.
Later, I did some looking-upping on the Boeing Stratoliner. Ten were built in the late 1930s and one-and-a-half remain. The whole aircraft, which was fully restored to flying condition, is in the Smithsonian's Udvar-Hazy Center. I saw it there in January 2010.
A lot of the technology in the Stratoliner was used in the B-17.
This boat/plane, as Anonymous coward said, belonged to Howard Hughes, who had enough influence during World War 2 to tell the government to keep its hands off his aircraft, at a time when all private aircraft were being commandeered for the war effort.
