I've booked many Alaskan flights through Delta and managed to get confirmed upgrades before the flight - which is an awesome benefit. I am looking to fly AA with some Alaskan segments built in and wondering if there is any way to get upgraded on those by perhaps attaching my Delta Skymiles number for those segments? How does the Delta/Alaska upgrade agreement work? Is it only delta-code shares that get upgraded or can I buy a ticket straight from Alaska or thru AA and still get upgraded as long as I am crediting to Delta Skymiles? Thanks.