I really don't want to start a riot here in the forum, but I must correct you, Hayhaa, and you are wrong there on JetBlue Airways. And in this post, I will do my best not to be bias, as I am a TrueBlue frequent flyer with them, and provide an outlook of the airline from a general point of view from the average US domestic passenger.
A lot of people still do remember the accident in Los Angeles involving one of JetBlue's A320s, however, that's been left in the past, and JetBlue has had a fairly clean safety record. I say fairly, because a few weeks ago, the nose landing gear of one of their Embraer 190's failed to deploy upon landing in Nassau, Bahamas. However, that E-190 still landed safely. However, I do want to say that your opinion on the satisfaction rate is a bit backwards. I have flone on JetBlue Airways since 2009, and have never had a single problem with the airline. In fact, I enjoyed my first flight with them so much, that they're basically the only airline I'll ever take between Florida and New York State. In fact, if I remember last year, that JetBlue has also received an award for being the #1 best airline in the US by passenger service, which I remember they have won that award multiple times. However, it only applies to their passenger service, not the overall size of the airline (number of planes and destination,) or overall valuation or recognition of the airline. Another thing about JetBlue that sets themselves apart from the other airline is the staff! Just wow, are the staff amazingly friendly! I even love how some of their flight attendants, or even the check-in crew comment me on the days I do fly with them with one of their JetBlue shirts on that I own. Ever since my first flight with JetBlue, I practically said to myself, "Where the heck has this airline been in my life?! I love this airline, they're amazing!"
Now, to add on on my least favorite airlines, I'm even going to include some that I've been on before that are unfortunately not in service today. My 5 list will also include airlines that I have never been on that I'll never dare fly on, or even step foot onto their planes.
#5; Transmeridian Airlines
I have flone on TMA before back in 2004 twice with my mother, and we really didn't appreciate the airline at all from how basic they were. Sure, they were trying to be a low-budget airline too, but when we flone on their planes, there was nothing to do but sleep. There wasn't even an airline magazine to read! It was basically like being on a normal city bus for hours. Plus too, my mother panicked when we returned back from New York on them into Orlando-Sanford, and they lost her bag that she did put travel insurance on. To this day, we never retrieved the bag filled with her make-up and expensive clothing.
#4; Frontier Airlines
I'll admit, I'm not a fan of low-budget airlines since they strip away everything and charge everything. However, I really do look down upon Frontier, because years ago, they had the same kind of in-flight entertainment that was on JetBlue at the time on their A319s. However, looking now at them is just terrible! They practically go from being an airline almost as good as my favorite airline I travel on, to being as bad as Spirit. It disgusts me on how they remove a feature from their plane that's really important in the airline industry for a lot of airlines and their passengers, being their in-flight entertainment; And also having those pre-reclined seats that you can't recline at all. I do understand that they are more light-weight, but its also sacrificing some passengers comfort, so they can squeeze in more seats. What I especially don't like about their seats is the tray tables. They are so tiny to the point where it won't be able to hold my laptop that I have, and barely have any space at all for your snacks or beverages you want, which of course you got to pay for!
#3; Air China
So I've heard stories from a friend who use to live in China, that he had some horrifying experiences from flying on board Air China. He hasn't brought up any flaws with their passenger service, so I have no idea what they do at the airport or on board during the flight, but the biggest complaint that he has stated out to me multiple times is how bad the pilots are. One story that stands out the most to me was that he was on board one of their 747-400s, and they were coming in to land, (don't remember what specific airport,) and he could easily tell their altitude, and was starting to get worried that by when they got down to 800 feet, he was getting really concerned at the pilot's actions, as they did not lower the landing gear until they were about 700 to 600 feet above the ground, while they were on final, close to short-final approach.
#2; Asiana Airlines
I have heard SO MANY horror stories about Asiana, such as how poorly trained the pilots were, as well as their passenger service. I think what struck me the most was their safety record, as I still remember to this day the Asiana 777 crash at San Francisco airport. I remember seeing the plane come in on TV, and saw it slam its tail into the sea wall, and it was horrifying seeing it spun around on the ground as it was grinding to a halt.
#1; RyanAir
Oh god... Where to even start with RyanAir... There is so much I can go on about RyanAir to the point where I need to write up an entire forum post about everything wrong with RyanAir. Basically, if I see one of RyanAir's planes or see an image of their CEO, Michael O'Leary, I will always look away and cringe at every second they've been mentioned.