For ASA back in the mid 90's when I interviewed, they asked a lot about Constant speed props, and Fuel Injection. Some guy didn't get thru the group interview because he couldn't basically explain the constant speed prop.

I'd know a thing or two about aerodynamics too. You can really impress them if you know that ground effect isn't a "Cushion of air" but rather a by-product of down-wash and a reduction in induced drag.

http://en.wikipedia.org/wiki/Ground_effect_in_aircraft

That one got me a "That a boy" by the CP and a offer on the spot.