The wikipedia article
(http://en.wikipedia.org/wiki/NATO_phonetic_alphabet) on phonetic
alphabets says:

"At some United States airports, the use of Delta for the letter D is
avoided because it is also the callsign for Delta Air Lines. "Dixie"
seems to be the most common substitute."

The tower at HPN has been known to take liberties with the alphabet on
Thanksgiving Day ("Advise you have information Turkey"), but I've never
heard dixie. Is this really common usage?