Also if you are in California the train or bus might be an option, I know there's a route that goes from Union Station to San Jose but I've never taken that one... don't know how efficient or reliable it is.
True. There's the Amtrak option for the train as well.
Generally speaking though, it costs more to travel out of state by train than flying. However, travelling within California by train can sometimes be cheaper than flying or even driving. (But that would depend on the season, and the distance.) I've traveled by train before, and I found it to be more pleasant than flying. You have more legroom than a train, you don't have to put your seatbelt on, (Because there is none) you can watch the scenery go by, and you don't have to worry about getting caught in a traffic jam.
But I wouldn't travel out of state by train because it becomes very expensive. (I try to travel by train within short distances only, and LA to San Francisco can be considered short distance by Amtrak.)
A sleeper cabin in a train for long distance trips is essential because it takes 4-5 days, (One way) to travel to the East Coast by train, and some cabins comes with a shower/restroom or there is shared restroom & shower room. (Trust me, you do NOT want to sit in coach for 5 days without a shower, and wearing the same clothes for 5 days.) I had a good friend who traveled once to LA on Amtrak in coach from Washington State for 36 hours, and he told me he would never do it again by coach. He couldn't sleep well in the coach seat, and he felt grimy when he was unable to take a shower, and wearing the same clothes for 36 hours straight. (He traveled in a sleeper cabin afterwards.)
Here's the link to the Amtrak train website:
Their baggage policy: