Range in any given vehicle of transport is generally understood to be the distance that it could travel without requiring to stop for any supplies necessary to maintain its normal performance.

It is, moreover, at least one quality in the aeroplane to which the designer may set a limit to his ambitions. With regard to speed, load carried, and so forth, he faces an endless task, but when range has reached a distance of just over 12,000 miles, equivalent to the greatest distance between any two points on the planet, his task in this respect is presumably at an end and in practice probably much earlier as the distance between which aeroplanes will need to operate will certainly be less than this.