This book describes in detail a method of direct optimization, which makes it possible to choose the best trajectory of an aircraft in conditions of its limited resource. This can happen in the event of an emergency on board, associated with both a possible equipment failure and external influences, for example, when lightning strikes an aircraft or collides with a moving object. The highlight of this book is the fact that the results presented in it can be applied universally to the choice of the flight path of large and small aircraft, as well as helicopter technology. In addition, they take into account various conditions of aircraft flight, including a possible accident. The methods and algorithms presented here can be used as the basis for the creation of automatic collision avoidance systems, as well as the choice of the best aircraft trajectory for flights in different regions and in different conditions.