My experience has been that, if I’m flying to a foreign destination, I’ll take a foreign flag airline if possible. British Airways is the one I’m familiar with. They have a coach plus class that’s really good. It costs about eighty percent more than standard sewerage. In return you get a seat that’s equivalent to an ordinary domestic first class seat and business class food. Just try, try to find that on a domestic airline running the same route. The BA,business class is also very good, offering a private compartment with a full stretch out seat.
In a former life I used to travel a lot internationally, i preferred Asian airlines first, followed by European. Cathay then Singapore were my favorites.
American carriers were the least desirable, United in particular, the stewardesses seemed to be POed at the world.