I usually use United - they seem pretty reliable to me.
John Sauce
I use JetBlue too.
Mary ALice Blanchard
Personally, I like. In the air flight Southwest. Flights I've been on has been most pleasant with no issues. I haven't had any reason to choose one over the other. I choose Southwest because they are more flexible on flights so I've been told.
Ari
I love flying with Delta, although American Airlines is pretty good as well. I haven't had the best luck flying with the non name brands honestly, I've only flown with them twice and both times I had delays. Plus you don't really get much when you fly with them, no food, no in-flight movies, no leg room, ect. But if you're looking for the cheapest option they definitely would be the way to go.