Just interviewed with Delta. I was the only military guy and the rest of the people were all ASA pilots in their mid to late 20's. Make sure you bring your FCC radio operators permit. They ask for it, but don't tell you to bring it. A few people didn't have theirs. The gouge mentioned on the previous posts is good. You could study that alone and probably pass the aviation knowledge test. The interview questions were mostly the same as well. The tests are all multiple choice on a computer. I interviewed first. 4 people, 2 pilots and 2 HR people. Very non confrontational and make you feel at ease. I did very well in the interview and thought I was a shoe in. Went in and took the aviation knowledge test. Did great. Then it came to the cognitive skills test. I have never in my life taken a test like this. If I had practiced for it I would have done fine. Not sure where you would get practiced up on it though. Anyway, they told me that I did not meet the mins on the cognitive test and that I could reapply in 6 months. They said they had some psycologists design the cognitive test to test your aviation skills / adaptability. It amazes me, I have no idea how I have flown an F/A-18 all these years!!! Best of luck to those that are going.