Often times upgrades are at the ‘bottom of the barrel’ — I’ve certainly been told “sorry” before when I have a confirmed upgrade on a flight that gets cancelled and the airline is offering me options for re-accommodation. They’ll happily put me on another flight, in the class of service that I paid for on my original ticket, but I can kiss my upgrade goodbye.
There’s a several years old policy at American, though, that I was just reminded of and that’s detailed at TravelingBetter.com. Upgraded tickets
that encounter a schedule irregularity may be protected into the upgraded cabin on any of our oneworld partners.
If your flight, for instance, from DC to New York to catch American’s onward service to London gets cancelled, your upgrade on New York JFK – London can be protected on the British Airways JFK – London flight or even on Washington Dulles – London non-stop.
This is apparently easiest to do when getting re-accommodated on one of American’s joint venture partners. An agent can just handle the rebooking themselves, for instance, if they’re putting you on British Airways, Iberia, Finnair, or Japan Airlines. They have a more cumbersome procedure trying to rebook onto other oneworld airlines but it can be done.
It’s important to know this, since not every agent knows this. Although American’s automated rebooking system is aware and has been known to handle this correctly on its own (at least with Joint Venture partners).
It doesn’t apply to domestic ‘sticker’ (500 mile or complimentary) upgrades at least in my experience. If I have a free upgrade on an American domestic flight, I won’t necessarily be guaranteed the premium cabin on an alternative flight — I’ll usually go onto the upgrade list even if there are first class seats for sale. Although I’ve never pushed to see if this policy really should apply.
But it’s clearly the case that for international travel, confirmed upgrades should be protected when you need to get rebooked — even on another airline. Buy a coach ticket, upgrade, and American will put you in business class on their partner.