This book, which is derived from my master thesis, presents a self-organizing medium access protocol called A3C. It was especially designed for aeronautical air-air communication. The book provides a detailed description of A3C, including a solution to the hidden station problem. Beside this, the book also provides a general overview of existing wireless medium access protocols and digital aeronautical communication. At the end of the text preliminary simulation results, dealing with A3C's overall performance, are presented.