[wkat4242]

And, at sea level. At altitude this no longer applies either because the circumference at altitude is greater.

[closewith]

Well, it still applies in aviation, as distance and ground speed used in navigation are measured at sea level irrespective of altitude.

[pbmonster]

...by around 0.1%. Which is why nobody is bothering with it, considering how susceptible to wind speed distances and velocities are up there.