On the surface that seems like such a simple question...

Looking at you profile, LMUs are probably the most reasonable option. They are offered, if available, when you check (T-24). Some have reported not being offered when checking in but when changing # of checked bags the option then became available.

For info on historical pricing check out this thread:

http://www.flyertalk.com/forum/air-c...ades-here.html

Other options are *A upgrade awards on AC, but you need miles in a *A program, a Latitude fare (Y,B), and codeshares and flights departing from certain cities (like MCI) are not elegible. the YYZ-LHR leg would work, but I don't know if the MCI origin messes this up.

Or, be sponsored by a Aeroplan member with eUpgrades (you must also be an AE member) and depending on the fare class (Tango fares are not upgradeable) and sponsor's status, and R availability (upgrades come out of this bucket) play the R games. Much electronic ink has been spilled talking about that!

So, LMU is your best option or buy up to a cheap Z if available and your travel policy allows.

Cheers,

Whitey in YUL