Used to be it was inexpensive to upgrade on day of travel to F. Years ago that is. Now this JNU based mom and son are returning home to JNU, beginning with BWI-SEA (AS 767) this evening after my 19 year -old son's 22nd, and hopefully FINAL leg surgery at Sinai Hospital's International Limb Lengthening Center. We've got side by side isles, but I'm hoping I can upgrade him on this long xc flight before we head home SEA-JNU on AS 75 tomorrow. We are waitlisted for upgrades, but that's not likely. Are inexpensive paid upgrades, for him, possible?