Southwest airlines is the best hands down. Especially if you will be renting cars and staying in hotels. Of course, they need to fly wherever you are interviewing. Otherwise the Continental, USAir, United group is the best. Recommend getting a credit card for your preferred airline as well. I racked up 2 free flights and Business Select status on Southwest.

I have to second that Southwest notion. They are hands down the easiest to deal with. You can schedule your flights early for cheaper and then if you need to change things up later if you have conflicting interviews (get ready for this to happen a lot) you can cancel the flight right up to the day before (at least it used to be) and still use all the money you put toward the flight for a different flight with no penalty. I lost a little too much money on other airlines when I had to change flights late in the game. I never lost anything by going with Southwest. Their rapid rewards program is okay (like all the others you have to do some serious flying to get a free flight). They also do a credit card which if you're into that can be a good deal.

Just to clarify, I don't advocate waiting until the day before to cancel an interview. Generally two to three weeks notice is considered minimum. It's just nice that you can cancel late if absolutely necessary.

Forgot to mention the changing of flights thing. I made changes day of flights when I finished an interview earlier than expected. It really helps you to buy flights early because you can A.) save money the earlier you buy and B.) change/cancel without penalty. I even bought a Southwest ticket and a US Airways ticket for one interview in the hopes I could make the southwest flight and get home 5 hours earlier. Missed the SW flight by 10 minutes but got all my money back. I would have gladly eaten the cost of the US Airways (the worst airline) to make the earlier SW flight. Its also nice on SW b/c you can always carry on a standard rolling bag or rolling garment bag b/c they use only 737's. I had to gate check a bag on US Air flight b/c it was small commuter jet and then had wait at baggage to pick it up after.

Thank you for the replies. This is all very helpful.

Anyone have any tips for getting discount rental cars?

priceline is really good for it.

Or an american express platinum...

Some time back, there was a jetblue deal that allowed for unlimited flight for 1 month for about 600 dollars. It would be ideal if they ran that promotion again.