I recently had AA cancel the first flight of my itinerary LGA (AA) YYZ (CX) BKK (CX) YYZ (AA) LGA. AA did not check me in for the flight LGA YYZ but I went straight over to AC and off I was. The reason was, that AA kept my booking open for a later AA flight, in case I did not make it on AC.

I have meanwhile received all my miles for the trip (including the nice 50K Business Class bonus for the CX flights between YYZ to HKG), however, no miles for the LGA YYZ segment. I could probably claim this now from UA (I do not have an AC account), but there is one more thing: I booked the trip online. AA gave me 1000 bonus miles for the return segment, but the other 1000 miles are still missing, I guess because I did not yet complete my itinerary.

Does anyone have experience with such a situatiuon: Would you go to AA or UA???