I'm searching for DTW-MIA-DCA on AA next Thursday, October 1st (need more miles on my way back from Detroit!). When I search on ITA, it's pricing as two one-ways, DTW-MIA then MIA-DCA, both in S class. However, when I go to price the route on AA.com using multi-city search, it's also pricing as two one-ways, but the DTW-MIA is in M class and MIA-DCA in G. If I search DTW-MIA and MIA-DCA separately on ITA, I also get M and G, just as on AA.com.

Why is ITA finding S inventory on the two one-ways that actually does not exist when I search as a connecting route? It's not as if ITA is pricing it as a DTW-DCA fare, which would be expected to have different inventory than the separate one ways.

And for what it's worth, ExpertFlyer also shows the same discrepancy. That is, S is available when searching as a connecting route, but only M and G are available when searching as individual flights.



ITA Results:




AA.com Results: