Why do boats and planes use knots instead of miles?

Question

Why do boats and planes use knots instead of miles?

Answer 1

Metric system.

Answer 2

The term knot was first used by mariners who measured how many knots on the line payed out in a given time period when the chip log was deployed

Answer 3

Ships and planes navigate using spherical geometry.  Vectors of planar and angular measures are used.  A nautical mile is a measure of arc on a great circle, not a linear distance.

Answer 4

because they used to pass a knotted rope under a boat/ ship to tell them how fast they were traveling and it;s stuck

Answer 5

It's used in nautical and aviation because both use navigational charts that are divided into "minutes".  A knot is a measurement of 1 minute of the 360 degrees of the earth.  It was first based on nautical miles and the way they measured speed using a knotted rope on sailing ships.  It has to do with the 360 degrees of the earth divided by 60 minutes.  It's equal to 1.15 statute miles.  

Here a good definition:  http://en.wikipedia.org/wiki/Knot_(speed...

Or:    http://www.onlineconversion.com/faq_07.h...