After World War II, the use of flying boats rapidly declined for several reasons. The ability to land on water became less of an advantage owing to the considerable increase in the number and length of land-based runways during World War II. Further, as the speed and range of land-based aircraft increased, the commercial competitiveness of flying boats diminished; their design compromised aerodynamic efficiency and speed to accomplish the feat of waterborne takeoff and landing. Competing with new civilian jet aircraft like the de Havilland Comet and Boeing 707 proved impossible.