This one is hard to believe. We've been planning a trip next March from Philly through London, and then somewhere in Europe either Italy of Madrid and return home. I've been watching fares this past month, missed a great price early June while we were away at friends and could not work out our details in time. Saw unbelievable price via Delta on Monday night, (~$585) which was gone later on Tuesday AM while we were awaiting info on our London accommodation. I was finding this on Kayak, instead of the usually reliable itamatrix software.
Checking again this AM, I found I could get us Philly-London and Madrid to Philly for $620. This did not show directly on Kayak, nor on American. But I noted that the price shown for this for American, previously ~$750, was now reduced to the price shown for Finnair, who sells this flight for $713. I clicked on "View Deal", and was taken to American Airlines site, and with a price of not the $714 shown on Kayak, but $620! I also noted similar price drops via this method on American for returning via Venice, Florence or Rome, and other multi cities, also direct to London ($590). While this is a bit more than the Delta flights that disappeared on me, they are both direct flights, the return does not leave Madrid so early that we have to rush around to get to the airport, and they do not make us deal with connecting back in Atlanta or JFK (we live just outside Philly). Put it through on American, and everything is in American.
In all the cases, the price drops were NOT available if simply searched for on American, but you get them if you get to American via Kayak and click on "View Deal". No idea why this is. But if anybody is thinking of going through London next March, you might want to look at this.