This book deals with one of the most important practical problems arising in airport logistics, the assignment of aircraft to gates. The research is based on data from ten major airports in North America, Asia, and Europe. The book provides an overview of problems, presents relevant literature and proposes new concepts covering unexpected events such as flight delays. These concepts were tested using practical data, and the algorithms can easily be implemented by the reader. From a theoretical point of view, new ideas in graph theory, stochastic optimization, and dynamic programming are introduced.