Ok, slightly complicated thing. I'm off to DTW in a few weeks and if I search for flights on AA.com I get a connection via ORD that gets me there at about 14:00, it involves a (slightly) tight connection in ORD of an hour and a half, but that's fine there are plenty of later flights if I miss it. If I search for the same trip on BA.com I can't get the same combination of flights, just some later ones.

Ah ha I hear you cry, why don't I just book on AA.com, well if I book on AA.com I get a fare code that will give me 50% tier points and Avios, on BA I can specify full tier points which is only about a tenner more than the lowest TP option.

So the questions are, why is the other connection available on BA? I guess I could call to book but then I guess I will have to pay an offline booking fee.