RC Airplane Controls.: "Transmitters with Four or More Channels
Ailerons really bring an airplane to life because they allow the airplane to roll. Most everyone that is serious about this hobby flies planes with ailerons. For this reason I want to focus our discussion of RC airplane controls on four channel radios.
A radio with four or more channels will have elevator/aileron control on the right stick and throttle/rudder control on the left stick. The ailerons are the primary turning control for an airplane with ailerons."