I redeemed 25,000 USAir miles in May to send my 17 year old son RDU-DEN-RDU to visit my sister in late July. USAir had no seats on that city pair available except 6 am, but their rules allow booking award travel on AA, so he was booked RDU-DFW-DEN-ORD-RDU. He was to get back to RDU at 11:37 pm Sunday. On Sunday July 30, his DEN-ORD leg was cancelled by AA about an hour before flight time because of AT delays at ORD. My sister had gone with him to check in at DEN. They told him that there were no more flights out that night. He asked if they could send him to CLT and I would drive there to pick him up (he did not really understand that the problem was DEN-ORD rather than ORD-RDU), and they told him "We can't say this any nicer, but you aren't going out tonight". They booked him First Class DEN-ORD-RDU at 9 am, and he eventually returned to RDU at 6 pm Monday, 19 hours late.

Question is, they apparently not only did not check on availability on DL DEN-ATL-RDU, which departed an hour later than the cancelled AA and wouyld have gotten him back to RDU just after midnight, but they could have put him on AA DEN-LAX an hour after the flight cancellation, then US LAX-CLT on the redeye then US CLT-RDU, putting him back at about 8 am, 10 hours before he eventually got back. I called AA and US, and there was avaiability all three legs. Question is, did AA have any obligation to book him on DL or on the AA/US combination when the AA flight was cancelled, since this would have gotten him back either 18 or 10 hours before they eventually got him back on an all AA routing? Remember it was a US award, and the award rules on the AA/US marketing agreement allow award travel on either airline on the award.