Cause all the logical ones were taken. There is no real logic to the three letter assignment. As an example the first 3 letter for Cleveland Burke Lakefront was CEL (Cleveland Hopkins was CLE at the time). It was changed at a later date to BKL. Al ----- Original Message ----- From: "Blaine Thompson" <phredd@xxxxxxxx> To: <AIRLINE@xxxxxxxxxxxxxxxxx> Sent: Thursday, July 15, 2004 2:56 PM Subject: FSD > Any idea why FSD (Sioux Falls, South Dakota) has that airport code? > > My hunch is FSD = Falls South Dakota, but my hunch has been wrong > before... > > Blaine >