My line of work requires me to travel, and I have had a chance to experience most of the major airlines. Here, then, is my ranking of the airlines based on personal experience:
#1 - Southwest - mainly for the fact that they have no first class, so everyone gets a bit more leg room. I like that. Also, the stewardesses are entertaining, and every time I have flown on Southwest so far they have been on time, or nearly on time.
#2-Delta. I say this grudgingly. Delta is the most expensive airline to fly on, but I have to admit they have not lost a bag, cancelled a flight, or messed up my travel anytime that I have used them. They are #2 because of expense, and also because the staff are not as friendly as Southwest.
#3 - US Air - US Air is #3 on this list only because I've had a long positive history with them in the past. Performance has, in my opinion, been weakening ever since they pulled their hub out of Pittsburgh. I feel pretty sure they will drop down (or off) the list based on the merger with American.
#4 - American Airlines [and American Eagle Express] - I have yet to have a quality experience with American Airlines. They delay flights, cancel flights, and lose luggage with an almost professional consistency. I avoid this airline as much as possible, but when it necessary to use them, I do so with great trepidation.
So there you have it - just a bit of a rant/personal observation/whatever. Take it for what it's worth.
2014_10_04: UPDATE.
I recently took yet another business trip, and I used United Airlines on this trip. I did not even include United in my original evaluation, because I have not flown United for quite some time.
What a pleasant surprise!
I flew United from Pittsburgh to Houston, and then flew their regional carrier from Houston to Shreveport, Louisiana.
On both the departing and returning flights, the planes were clean, I had adequate leg room in economy class, and every United employee I encountered was friendly, gracious, and helpful.
I had an accidental chance to test their customer service when I inadvertently left my Samsung tablet on the regional carrier flight in Houston. I realized, as I boarded the flight for my Pittsburgh leg, what I had done and notified the stewardess. She came back a few minutes later and told me that they found my tablet, but because our flight was nearly ready to leave they would probably have to ship it to me.
Just a short time after that, the stewardess reappeared with my tablet. Apparently United employees had traversed almost the entire length of Houston airport (or maybe sent the tablet across the tarmac somehow) in any case, United employees got the tablet to me, and even though the airplane door was already closed they were able to pass the tablet to the pilot via a window in the cockpit.
All of which to say, I had perhaps the first truly pleasant flight experience in a long time with United, and I look forward to trying them again; I'll be curious to see if this experience is consistent.
