In another thread, someone mentioned that only 13% (or something like that)
of the possible 3-letter combinations are currently used as airport
identifiers. Given this fact, why in the world did they start mixing
numbers into the scene?

For example, why "C89" (for Sylvania Field, in WI) instead of some letter
combo?

Anyone know why the identifiers are a mix of letters and numbers the way
they are?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"