Just a quick note for those who have been compiling the lists of what code belongs to what, D005150 is NOT specifically the National Charter Schools Conference. I've been tracking the code off and on for the past 18 months and still believe that it is a generic event code that is somehow tied to events that have a negotiated group airfare discount available from American Airlines. It seems like a year ago or so that I actually read an event web page that said something along the lines of "and American airlines is passing along their great Avis discounts for event attendees etc." I keep checking back in here hoping that someone can confirm what it really is but have yet to see that. Sometimes it gives such good rates that it scares me a bit. Here are some of the events that I'm finding at this moment that it has been affiliated with just so people know that National Charter Schools isn't the sole answer.

Americas Conference®
New Leadership—New Focus:Good Governance and Economic Development in the Hemisphere Oct 1-3, 2008 Miami.

2007 CREOG & APGO Annual Meeting
“Innovations in Medical Education:Achieving Your Potential”
March 7-10, 2007 Salt Lake City
That brochure apparently confirms that this code is tied to events and American Airlines. "American Airlines customers may take advantage of the best possible car rental rates available with AVIS. Reservations can be made by calling AVIS directly at toll-free (888) 754-8878 or online at www.avis.com, referencing AWD #D005150."

DatBoiEntertainment Ultimate Spring Fling 2009
Las Vegas, April 10-13 2009.
"contact Avis at (888) 754-8878 and use our Avis Worldwide Discount (AWD) number D005150 or reserve online ..."
Oh, great, that last one is probably going to get me in trouble if the sys admin here at work ever checks the internet log. Guess I'd better quit on this search while I'm only so far behind.

Anyway, I guess that's enough to give the picture that the code is event driven with no common thread for the type of event. Not sure how long it's kept active in any particular market before or after an event. I've seen in some event materials that it's valid a week before and a week after the event. However, I've used it well outside an event window, though I can't say at all if there was maybe another event in the area at that moment of my booking that had the code active.

When I first found it I remember that one event was "Brad and Tammy's wedding" and another was some kind of vodoo-ish dance and music festival somewhere in the Caribbean and I got the sense that it was probably a clothing optional kind of thing.

Also a lot of scientific and business conferences get the code too. (E.G. Fifth International Symposium on Beamed Energy Propulsion (ISBEP 5) Outrigger Keauhou Beach Resort, Hawaii, November 12 - 15, 2007)
Gee, that one sounds like fun even if they didn't hold it in Hawaii. Does this entail using a phaser to power your starship instead of using it to blow up Klingons? Can't believe I missed ISBEP 1 through 4 too.

This code recently reduced a 3 day Denver rental for a mid-size over the weekend from $183 to $118 before coupon application.