Why didn't aviation ever go to the metric system?

Serious consideration of what became known as the metric system began in 1789 in France. read more

The knot, or nautical mile per hour, is very closely linked to the Earths rotation, and therefore navigation. Since the second is a fundamental SI unit, the knot is, in a sense, a derived SI unit itself. read more

One, because all of our other major trade partners used the metric system. Two, as the USA was — and still is — our largest trade partner, the switch to metric eliminated the confusion that arose between the two different Imperial systems; British Imperial and American Imperial. This was probably a unique Canadian problem. read more

Politics and economics have been the real incentives to go metric. The world’s most anti-metric nation—Great Britain—grudgingly began to ditch its Imperial system in the 1970s because it was the only way to gain access to the markets of continental Europe. read more