As someone who has used flyers in this event before I'd say that there is a reason I tend NOT to bring them. Apart from the fact they tend to be pretty expensive for the force (and can only ever provide fire support) they suffer from the fact that anything can shoot them down!
Sitting out in view every single time pretty much any weapon has the potential drop them out of the sky. The fact that some armies find this more difficult (such as necrons or dark eldar) is offset by the fact that it is crazy scary to see imperial guard armies packed with hydras... and you take the risk of getting pwned utterly and having your day ruined!!
Add to this that they might not turn up until half way through the game and you can be pretty certain that the only army with a secure way of fielding flyers is probably actually the tau, eldar or guard (and these all involve ensuring your army also has a dedicated reserves bonus)
In any case, if it makes you feel any better lor, popsical is probably using a TX42 piranha with fusions (because it costs the same as a regular piranha with fusions but is way better), a XV9 Hazard suit, (because its sexy... probably with cascades), and at least two tetras (because they are mad laser pointers!)
Also, g00gle5, can we hold iain to using a unit from the very hungry catepillar!?
Finally, GW stores (and stores in general) are not libraries. You will only have knowledge of the different armies if you own all the books, or have borrowed them from a library! You are NOT expected to have knowledge of any opposing armies (and this is true of all tournaments). This is why you bring your own army rules to a tournament and not every single army book. That you have knowledge is an advantage to you, but is not a necessity and definately not expected.