The way of a man in the air had yet to be discovered.
The starting point of their theory of flight seems to have been that man was endowed with an intelligence at least equal to that of the bird; and, that with practice he could learn to balance himself in the air as naturally and instinctively as on the ground.

He must and could be, like the bird, the controlling intelligence of his machine.

To quote Wilbur Wright again: "It seemed to us that the main reason why the problem had remained so long unsolved was that no one had been able to obtain any adequate practice.

Lilienthal in five years of time had spent only five hours in actual gliding through the air.

The wonder was not that he had done so little but that he had accomplished so much.