Im sort of in the same position as you and although I dont know anthing specific, I`ve been told that these tests consist at the first stage of loads and loads of algebra/mathematical problems which have to be solved quickly. If you pass this you then go onto other stages including interviews...
These initial tests might not have all that much to do with being suited too flying, but they are designed to whittle down the extremely large numbers of applicants to a small percentage for interviews.