Small sacrifices must be made.

All flight is based upon producing air pressure, all flight energy consists in overcoming air pressure.

No one can realize how substantial the air is, until he feels its supporting power beneath him. It inspires confidence at once.

We returned home, after these experiments, with the conviction that sailing flight was not the exclusive prerogative of birds.

Small sacrifices must be made.

One can get a proper insight into the practice of flying only by actual flying experiments. . . . The manner in which we have to meet the irregularities of the wind, when soaring in the air, can only be learnt by being in the air itself. . . . The only way which leads us to a quick development in human flight is a systematic and energetic practice in actual flying experiments.

Of all the men who attacked the flying problem in the 19th century, Otto Lilienthal was easily the most important. ... It is true that attempts at gliding had been made hundreds of years before him, and that in the nineteenth century, Cayley, Spencer, Wenham, Mouillard, and many others were reported to have made feeble attempts to glide, but their failures were so complete that nothing of value resulted.