you would measure distances in centimetres, metres and kilo metres.
Miles or Kilometers
To measure the distance of stars you have to measure by light years.
You would typically use millimeters (mm) to measure the thickness of a coin. This unit is commonly used for measuring small distances or thicknesses.
Usually Miles or Kilometers
metres, kilometres .................................
Light year is used to measure the stellar distances whereas miles and km is used to measure distance on Earth.
The best unit to measure the distance from Fairbanks to Anchorage would be miles or kilometers. These units are commonly used to measure long distances between cities and are widely understood.
AU is not used to measure the distances on earth, because a astronomical unit is a unit of measurement equal to the distance between Earth and Sun. So that's why you cannot use Au for measure the distances on Earth.
I would typically use kilometers to measure the distance between Delhi and Mumbai, as it is a commonly used unit of length for measuring geographic distances in India.
Kilometers
Because it is a large number, suitable for large distances. Astronomers also like to use the unit Parsec.
You would use the unit of measure called "kilograms" to measure the mass of an elephant.