Why don't airports have runways on a slight incline?
Many airports do have slightly sloping runways, but this incline is likely to make little difference in the grand scheme of things.
Asked by: Billy Doyle, by email
Many airports do have slightly sloping runways - the small landing strip at Santa Catalina near Los Angeles is one example. But a decline doesn't aid take-off, or an upwards slope help with landing. Given the power needed to get airborne, a slope makes little difference either way. The most important factor is wind: planes take off with the wind to maximise airspeed, and land into it.