A few years ago I planned a trip from Washington, DC to India, leaving around Christmas and returning mid-January ---- not the best time to look for free or upgradeable seats. I looked at everything I had access to -- DL; AA; BA; NW; AF; Alitalia; even Aeroflot was a possiblity. It was very difficult as these routes are very busy and even more so around Christmas/New Years.

I gave up on the freebies and finally booked upgradeable coach seats on DL via JFK (certainly not the cheapest Y seats), then via FRA and now via CDG, and, with flexible days, was able to get confirmed upgrades. But, there certainly was a possibility that I was going to go coach, which would have been an experience I'd prefer to avoid....

Good luck.