A little background: I am travelling for business on CO in June to GIG. I wanted to go on AC and avail myself of an upgrade cert, but CO was so much cheaper that I had to take it (no bottomless expense budget here!); I am going YYZ-IAH-GIG on CO, then the same routing on the return.

I am asking: what are CO's policies for upgrading at check-in? What are the rates for this or comparable routes you have encountered?

It will of course be pricier than the free AC upgrades I enjoy, but I would like to experience BF on CO, and also doing it on my own dime if the price is right.

Thanks in advance!