Speed enforced by aircraft what does this really mean

Just take 3600 (seconds in an hour) and divide it by how many seconds it takes to go a measured mile.

Simple.

Also works for kilometres the same way.

 

I've been as fast as 160kph. Bit of a rush.

Just saw a video of a Hennessy Venom GT doing a 0-300kph run in just over 13 seconds.
First gear took him to around 111km. Would be interesting, to say the least! And he had 5 more gears to go.