On a December afternoon in 1935, precisely thirty-two years after the Wright Brothers first stirred the sands of Kitty Hawk, a new silver ship rose from Clover Field in Santa Monica, California. Douglas Aircraft Company vice president and chief test pilot Carl A. Cover lifted the Douglas Sleeper Transport into the sky over the Pacific, and with that modest takeoff, the DC-3 era began. It was not merely an airplane; it was the arithmetic that finally made air travel profitable. For the first time, an airliner could carry enough passengers—twenty-one in the day version, fourteen in berths at night—across a continent without the crutch of a government mail subsidy. American Airlines took delivery in July 1936, and by the year's end the DC-3 had woven itself into the sinews of American commerce. Its strong, multiple-spar wing and all-metal construction gave it a ruggedness that would see it through war as the C-47 Skytrain and back into peace as a cargo hauler, missionary transport, and skydiving shuttle. More than thirteen thousand would be built in all their guises, and even ninety years after that first flight, the faithful old Gooney Bird still graces skies from Alaska to the Antarctic, a living testament to the day aviation finally learned to pay for itself.