Mental arithmetic, hand eye co-ordination (games consoles good practice for that), short term memory. Also when you sit them, take a botte of water, and maybe a nutrigrain bar in with you!
If you go to OASC and pass the aptitude for pilot for the RAF, does that also include a pass for the navy? The only reson I ask is that you can do the aptitude tests twice. So if you do them twice for the RAF and pass, but dont eventually get in to serve, can you apply to Navy as Pilot and use the RAF aptitude results?