Even before the first DC-3 had ever flown, Douglas planned to produce a four-engine transport about twice the size of the DC-3 and, in 1938, developed the DC-4E (E for experimental) to carry 42 passengers by day or 30 by night. It had complete sleeping accommodations, including a private bridal room. The DC-4E featured many innovations; it was the first aircraft of its size to have a nose wheel, and full pressurization was planned to be installed on the production aircraft. The single prototype proved too expensive to maintain, so airlines agreed to suspend development in favor of the less complex DC-4.