"The supporting powers of time air and of the wind depend on the shape of the surfaces used, and the best forms can only be evolved by free flight through the air."

“The contrivances which are necessary to counteract the wind effects can only be understood by actual practice in the wind.”

“The increasing size of the apparatus makes the construction more difficult in securing lightness in the machine; therefore the building of small apparatus is to be recommended.”

“Lilienthal's appendix from Chanute's book Progress in Flying Machines”

“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.”

“The maintenance of equilibrium in forward flight is a matter of practice, and can only be learned by repeated personal experiment.”

“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.”