Upgrading a reward flight

Absolutely no UC reward seats available for months around our required dates, but an odd PE here and there. I have been checking since 11months out and there has just been an odd individual seat! Is it possible to book the reward PE and upgrade at the airport if seats are available? Thanks.

[mitchja]

Yes you can do this at anytime virtually right up to the flight departing.

I upgraded a U (Premium reward which even started as an economy reward fare before I reached check-in) with miles about 30mins before departure in the CH a few years ago!!

You would have to pay any difference in tax at the same time though.

Ah thanks. Might be worth giving it a shot.