Actual practice in individual flight presents the best prospects for developing our capacity until it leads to perfected free flight. - Otto Lilienthal

By practice and experience a man can (if the wind be of the right strength) imitate the complete sailing flight of birds by availing himself of the slight upward trend of some winds, by performing circling sweeps, and by allowing the air to carry him.

Artificial flight may be defined as that form of aviation in which a man flies at will in any direction by means of an apparatus attached to his body, the use of which requires personal skill. Artificial flight by a single individual is the proper beginning for all species of artificial flight, as the necessary conditions can most easily be fulfilled when man flies individually.

The difficulty of rising into the air increases rapidly with the size of the apparatus. The uplifting of a single person, therefore, is more easily attained than that of a large flying machine loaded with several persons.