My brother has booked a ticket on aa.com CLT-ORD-DEL (and back) and I would like to use my SWUs for his flights between ORD and DEL. Would one SWU upgrade both the CLT-ORD and the ORD-DEL legs? The wording on their web site seemed to suggest that: This upgrade is subject to capacity controls and is limited to a single one-way trip with a maximum of three segments. Is my understanding correct, and what happens when some segments are available for upgrade and some are not? I only want to use the SWU if the ORD-DEL flight can be upgraded.
What is the priority by which the upgrades are done? I presume that since he does not have elite status with AA, he would be at the lowest priority.
Yes, one SWU will upgrade both segments.
If only one segment is available, you can upgrade that one and wait list the other segment. In your situation, just tell the agent that you only want to use the SWU if you clear the long-haul segment. They can wait list just the ORD-DEL flight, then clear the domestic segment later assuming there is upgrade inventory.
Priority is by status, then time of upgrade request within each status level. (If you don't clear the upgrade by flight check in, then you'll need to be added to the airport wait list, which is then prioritized by status, then time of check-in within each status level.) If your brother is traveling with you on the same PNR, then he will inherit your status. Otherwise, he would be placed behind all elite members.