I'm trying to book flights back to the UK from the US for my family in October and was hoping to find flights that could be upgraded with miles as we have a lot of miles, but not enough to send all four of us business. I signed up for an Expert Flyer account and the only flights that seem to be showing that they have seat availability for upgrading with miles are the BA-operated ones, but you need to book a fare with booking class Y to qualify with BA for mileage upgrades. Expert Flyer says there are Y-class flights available to book, but the only flights showing on the AA website are Q & O. Any advice on how I go about finding elusive Y-class flights to book? Or experience with expert flyer and how accurate they are?