Okay, a little miss leading. The first (and only) flight for the Hughes H-4 ("Flying Boat" as Howard Hughes called it) was on 2 November 1947, 63 years ago today. The H-4 is more commonly known as the Spruce Goose. It is still the world's largest airplane by wingspan at 320' 11" (97.54 m). It flew for about a mile, and reached a maximum altitude of about 75'.
It was designed to have a MTOW of 400,000 lbs (180,000 kg) and a max range of about 3,000 nm (4,800 km). It was powered by 8 P&W R4360 "Major Wasp" engines, each with about 4,000 hp. The H-4 was designed to move cargo, including heavy and outsized cargo (such as the M-4 Sherman Tank) as well as up to 750 troops.
It was initially a joint venture of both the Hughes Corp. and the Kiaser Co. (who built the famed Liberty Ships) and was originally called the HK-1.
Although the project did not move beyond the initial prototype, the H-4 Hercules was a forerunner of the massive transport aircraft of the late 20th century, such as the Lockheed C-5 Galaxy, the Antonov An-124, and An-225 the Boeing B-747 Jumbo Jet and the Airbus A-380.
Even though there was a US Military contract for the H-4 during WWII, it was never given a military aircraft designation. The military contract was cancelled after WWII ended. If it had entered service, it would have been flown by the USAAF (which was actually the USAF by the time it flew) and the USN.
[Edited 2010-11-02 10:14:26]