From what I have read on this forum and my personal experience, it is my opinion AA will honor the guarantee if the difference is under some set price, say $100 or less, I don't know what that actual figure is. If it gets over that amount AA basically tells you to get lost.

It happen with me a couple of years back with a fare on Orbitz that was several hundred dollars lower than aa.com. They refused to honnor the low price guarantee, even making excuses that time on my computer was in a different time zone than the FAX machine I sent the "proof" on. For the day and a half I spent arguing with them the price remained lower on Orbitz and Expedia. They finally stop responding. I cancelled the aa.com and bought it on Orbitz and chalked it up as a $100 (change fee) lesson learned.

UR