Aircrafts and aerodynamics
Airplane Parts 
The main parts of an aircraft are: the fuselage, the wings, the horizontal stabilizer,the vertical stabiliser, the landing gear, and of course the engine(s)
Aircraft Forces 
Four Forces on an Airplane 
The four forces which act upon an aircraft are:
- LIFT acts upwards at right angles to the airflow through the centre of pressure.
- DRAG is the backward force which opposes the forward motion of the aircraft and and acts parallel and in the reverse direction to the aircraft movement.
- THRUST is the forward propulsive force provided by the engines.
- WEIGHT is the total weight which acts vertically downwards through the centre of gravity.
NASA's Beginners Guide to Aerodynamics - Supplement your of study aerodynamics at your own pace and to your own level of interest. Some of the topics included are: Newton's basic equations of motion; the motion of a free falling object, that neglects the effects of aerodynamics; the terminal velocity of a falling object subject to both weight and air resistance; the three forces (lift, drag, and weight) that act on a glider; and finally, the four forces that act on a powered airplane. There are many interactive pages designed to illustrate aerodynamics.
Aerodynamics Lesson - Gold Seal Master CFI trainer Robert Still video presents basics of Aerodynamics in an easy to understand format.
See How It Flies - Free online book (in HTML format) running through aerodynamics and techniques for flight.
Wikipedia Aircraft - A definition of Aircraft and examples of various types of aircraft.
Wikipedia Aerodynamics - Technical overview of aerodynamics and the physics of flight.
FAA Aircraft - FAA information on Registration and Certification of Aircraft, Advisories and Guidance, Regulations and Policy, Forms, and Technical Information. Includes a searchable database of aircraft registered in the US.