In the early days before electronic navigation, many barn roofs and
water towers had the names painted on them.

You can thank the gals:

http://www.ninety-nines.org/airmark.html

Airmarking:
"This program of identifying airports to pilots was started as the National Air
Marking Program. This program was the first U.S. government program conceived,
planned and directed by a woman with an all-woman staff. The program was a part
of the Bureau of Air Commerce."

And a rather sad interlude -- "But then came the war. After the bombing at
Pearl Harbor in 1941, the U.S. Government determined that marked airports along
the east and west coast were obvious targets for enemy identification and
attack. Consequently, Blanche Noyes, who had set about the work of marking some
13,000 sites, went about the work of blacking out those very markings she and
her team of women pilots had diligently created."