Originally Posted by
ashill
What sdsearch thought they observed was the other way around. IB had availability BOS-MAD. AA did not have availability on LAX-BOS (standalone) but apparently did have availability on LAX-BOS-MAD (as well as BOS-MAD standalone). That is certainly within AA's powers to do; whether they do is not really clear (because what sdsearch really observed was that LAX-BOS wasn't available after, not before, they booked their ticket).
Actually, it was LAX-JFK outbound, BOS-LAX inbound. U availability (thus business class on the LAX-JFK 3-class, first on the BOS-LAX 2-class).
Anyway, I think I was wrong. I just did some other searches for research purposes only, and found that on Sep 8 at this moment there is LAX-(AA)-JFK-(IB)-MAD-LIS as well as LAX-(AA)-MIA-(IB)-MAD-LIS in U, but the very same 6 am-ish flights LAX-JFK and LAX-MIA are indeed available by themselves. (There's no nonstop availability on LAX-JFK at any other time of day, though. There is, btw, multiple "pages" of 1-stop U availability on LAX-XXX-JFK that day. And, btw, if all you want to fly is LAX-JFK, you have to pay 7.5k miles more to do the nonstop than to do a 1-stop.)