“TWA Douglas Airliner — Fastest in the air — Slowest to land”. This detail from a Transcontinental & Western Airlines postcard shows how the innovative “speed brakes” — primitive flaps — on the trailing edge of the wing and even under the fuselage of the DC-2 aircraft, improve its landing characteristics.
With the flaps, and starting to land from an altitude of 100 feet at end of the runway, the DC-2 could land at 55 mph (89 km/h) and touch down within 500 feet (152 metres) of the end of the runway. Without the flaps, it would have to land at no less than 70 mph (113 km/h), and would touch down within 1,500 feet (457 metres) of the end of the runway. (In practice, a pilot would plan to touch down as near the end of the runway as possible.)