Hobbyzone offers about 6 different channels for the Super Cub RTF, as zoott mentioned. Just make sure you purchase two different frequencies and you'll be good to go. If you buy from a local hobby dealer, there will be a sticker with the plane's channel on the outside of the box. If you order online, just request two different channels. If you order at two different times online, whoever purchases his plane last just has to request any frequency other than the first.

Good luck and good shopping!