if you’re going British Airways and are traveling coach, check out the BA “World Traveler Plus” class of service. You get a seat and space that are essentially what you get in domestic U.S first class for about 80% more than you’d pay for coach. I’ve done it twice and it’s well worth the additional cost.
I'm actually flying business class on American. I booked it with points, I could never afford to fly that way paying cash!