I am going to NYC this spring break with my friend. I'm UA 1P. I found 2 itienrieies: SEA-IAH-LGA(CO) and SEA-ORD-LGA(UA) on Tuesday. He never flies F so I really want him to get upgraded. I'm fine at the back of the plane. I prefer SEA-ORD-LGA since it's on UA metal. my friend can upgrade with me at 72 hrs mark.However, I don't have any experience on this route so I am not sure how hard to get upgraded. There's a slim chance for him to get upgrade on CO since they only upgrade companion at the gate. However, CO 737-800 has more seats than UA A319. Should I go with UA or CO? is it possible for me to get my companion ELR seat on CO for free like UA Econ +? Thank you so much!