I was booked on an itinerary with a transatlantic leg which two days ago was J3, travel on Sept. 15, Y booking code. My wife had a confirmed J seat on an Aeroplan reward.

J inventory seemed to be lowering by a couple of seats every other days. However, the seat map showed nearly half the J cabin available.

I ended up (1) paying a $90 change fee plus extra $50 in "taxes" to change her Aeroplan ticket and (2) buying a EUR 100 intra-Europe ticket for myself, so we now are both confirmed in J. Flying LHR-YYC nonstop instead of connecting at YUL.

Bottom line, don't trust seats maps.

Also, looks like sometimes AC inventory management is not all that bad.

I might have ended up getting an upgrade at the gate on our original res. However another $230 is well worth the confirmed upgrade peace of mind.

But again, seat maps are a poor indication of actual loads.