Design evolved during mid-40s in response to a need for a more modern replacement for the DC-3 and in response to the airlines' requirements for a new passenger aircraft. Result was Model 110 which became basis for 240. 40-passenger 240 designed for medium and short-haul operations with fuel and payload adjusted for optimum range. One of the first 2-engine airliners to be pressurized. Because of cabin pressurization, aircraft can climb and descend quickly without affecting passenger comfort. Allows shorter trip times and higher profitability for airlines. Could cruise at about 290 mph at range up to 760 miles. Had some unique safety features, such as automatic feathering, reverse pitch props, and ample single-engine power in event of engine failure at takeoff. Aircraft was primary navigation trainer for USAF for several years and also used as utility transport.