Originally Posted by
worldtrav
Yes, sometimes.
What I can't fathom on BA is they won't let you use your Avios at the gate/airport on the day of departure to upgrade, they let the seat go empty.
To be clear you can do it on day of departure, but through the normal channels online or via call centre if the availability is there. If you've already checked in that makes it more difficult as you'd need to get unchecked. Usually availability opens up (if it's going to) a day or two before rather than on the day itself.