Just about every airline question ever asked is somewhere in the Ryanair interview thread. It will take you all day but worth a read.
My suggestion would be to open up MS Word and copy and paste the questions that people say come up at interview. Things like advantages of a swept wing, what causes wind, interpreting a sig wx chart, principles of a VOR, what is the radius of the MSA, how does TCAS work etc etc.
The above will cover the technical side of things. Then you will need to research the airlines you are targeting and also make sure you can ask all of the tricky "HR type" of questions such as give us an example of when you encountered conflict and how did you resolve it. Or what are your strengths and weaknesses. A good interview technique book should cover the latter and more importantly give an explanation for why the interviewer is asking about this so that you can plan an answer accordingly.
You will end up with literally hundreds of questions to work through. You can then go about researching the answers or double checking the ones in that thread if given.