I has a similar brain lapse in MIA on a layover not too long ago between LAX and EZE. Left my iPhone on my seat on the LAX-MIA leg, and it wasn't until I was in my seat on the MIA-EZE flight that I realized it was missing. I panicked, told the FA, and she literally ran up the jetway to see if she could do anything. About 20 minutes later, a Gate Agent shows up literally dripping with sweat and hands me my iphone just before they shut the door. I kid you not. I can't tell you how thankful I was as the trip to EZE was three weeks!
I wrote a long gushing email to AA thru their website listing the names and crew member numbers of those who helped me (I made sure I got all their info)