I've flown a lot in my life. Some of the better (IMO) airlines don't exist anymore. (TWA among others)
As for the "BEST", it depends on where you're flying to/from. Going from Kahleeforneeya to Hawaii, I prefer Hawaiian or Aloha. 2nd choice wo uld be UAL.
ATA (IMO) sux..like being stuffed in a fvcking cattle car. They seem to cram more people into an airliner than the rest. I guess to make up for the heavily discounted fares companies like Pleasant Hawaiian have negotiated.
Southwest does have some cheap fares, but, often, Jet Blue beats their fares, IF their routes fit your travel itinerary. Having the TV in the seatbacks is kind of nice. Gives you SOMETHING to watch besides the usual crappy movies, and for short flights, you don't get movies anyway...(wonder if they let passengers watch the unfolding drama a couple of years ago, when they had the front landing gear problem?)
I've flown Alaska a few times, and IMO, as long as you don't have to make a leg on thier "partner" Horizon Air, they're pretty good. The Horizon fleet always seems to be 2nd rate IMO.
NWA used to be pretty good. I understand their service has gone into the crapper in recent years. Probably causing some of their financial problems, which have led up to their bankrupcy filing.