DJ,
it would depend on the size of the kit you are thinking of. the AAs motors put out roughly 10 grams of thrust, so it can lug around 20 or so grams of weight (i know it can carry more, not sure how much though, but lighter is always better). if you're talking about the stick and tissue kinds of kits, like the one Quint-RCU is doing here:
http://www.rcuniverse.com/forum/m_3946048/tm.htm then the weight might be too much. the AAs electronics alone comes in at about 10 grams, so you're left with 10 or so grams for the airplane itself. i have seen a few of those rubber band powered free flight Guillows planes, and even the hand toss style planes (those little 5 dollar ones) used with the AAs electronics and it seemed to work just fine. i'll try to find a picture.
i did RC cars for many years, i still have my old original Associated RC-10T and Tamiya BlackFoot that i kick around sometimes (they're almost collectors items now!). i didnt get into RC flight till a couple years ago and i find it a lot more fun than the cars. its a lot more work than the cars, and takes a lot more patience, but its much more rewarding (especially when you build your first one and see it fly for the first time).
fredbobjoe,
the Plank has been built by a number of people and they've seemed to have good success. i havent built it yet (still waiting to build my hot wire foam cutter), but the instructions seemed pretty clear cut so i'd imagine you wouldnt have much problem with it.
nick