"We could not understand why the calculation of Lilienthal and others were so much in error."

"We do not intend to make a fortune out of this, but to make a machine that will fly."

"It is not disputed that every person who is using this system today owes it to us and to us alone."

"Success in inventing depends on the close observation of nature."

"The greatest pleasure in life is to do what people say you cannot do."