As late as 1977, the party that commissioned the H-4, the U.S. government, was thinking about flying it again. The U.S. government almost embarrassed itself twice.

The idea for a giant seaplane was initially championed by industrial magnate Henry Kaiser, who had masterminded the Liberty Ship construction program, which cranked out freighters in an unbelievable 48 days (record: five days). Kaiser wanted to transport war materiel overseas by air, where it would be safe from enemy torpedoes. But he knew nothing about airplane building and was happy to hook up with Hughes, who'd assembled a team of crack aeronautics engineers that, among other things, helped him design a plane that set a speed record in 1935. Despite opposition from the military and the aircraft industry, Kaiser and Hughes landed a government contract to build three prototype planes. The catch: the long-shot project could make only minimal use of strategic materials such as metals. That meant using wood, common in small aircraft but untested in one so large.

Hughes's eccentricities hobbled the project from the start. Kaiser found his partner impossible to work with and was relegated to the sidelines. Hughes micromanaged every design detail, and work soon fell far behind schedule. By early 1943 the metals shortage had eased and many urged that aluminium be substituted for wood, but Hughes, apparently enamoured of the advanced plywood fabrication methods his team had developed, declined to switch. Sceptics almost succeeded in killing the project in 1944, but somehow Hughes got the OK to continue. The war ended before the plane was assembled into one piece. The project dragged out until 1947, when a U.S. Senate committee began investigating Hughes for defence contract irregularities, particularly regarding the Spruce Goose. As if to demonstrate that he hadn't defrauded the government, Hughes, who always test-piloted his own planes, flew the H-4 about a mile in less than a minute during what was supposed to be a taxiing test on November 2.

Why did Hughes never fly the plane again? Some said he was afraid to, but his closest associates denied it. The explanation is that the Long Beach authorities had prohibited Hughes from actually flying the aircraft in their harbour. The short hop made by Hughes resulted in the Spruce Goose being confiscated by Long Beach.

The war was long over. The need for big seaplanes had evaporated. Wood construction was obviously a dead end. Even before the flight Hughes admitted that the plane was too large to be economical. Claiming there were still research lessons to be learned, he stubbornly kept the work going until around 1952. But he was distracted by other ventures and increasingly reclusive. Eventually everyone moved on to other things. After Hughes's death in 1976, the plane was put on exhibit and now may be seen at the Evergreen Aviation Museum in McMinnville, Oregon.