[gjm11]

I think they hope that

1. Given the choice between just using Orbitz and not seeing AA flights at all, and using two sites instead of one, customers will choose to use two sites instead of one.

and then, after they've got used to that,

2. Given the choice between just using Orbitz+AA and not seeing (say) US Airways flights at all, and using three sites instead of two, customers will choose to use three sites instead of two.

and so on, until eventually

N. Orbitz goes out of business because it's no longer getting enough use.

and/or

N'. Customers give up doing comprehensive price comparisons.

at which point

N+1. All the airlines (including AA) get to increase their prices.