Can anyone help?
 

We've just come back from our road trip around the South Western states and, thanks to the wonderful people we met and the great service, we had an amazing time!

One odd thing that we kept encountering on our trip were huge chalk letters in the hills, we thought that perhaps these were navigation aids to light aircraft? Can anyone enlighten me?

Best wishes, Kate

The letters on the hills are usually the first letter of the town's name; many times put up there by school kids. In the flatlands, towns have their name on water towers.

Many thanks, another of life's little mysteries is solved!

Is this one of those mysteries like the shoes hanging on the wires?

Usually these letters are put there by kids to display the first letter of their high school. Example...B...for Basic High School.