"Sometimes we stare so long at a door that is closing that we see too late the one that is open."

"Great discoveries and improvements invariably involve the cooperation of many minds. I may be given credit for having blazed the trail, but when I look at the subsequent developments I feel the credit is due to others rather than to myself."

"A man, as a general rule, owes very little to what he is born with - a man is what he makes of himself."

"Concentrate all your thoughts upon the work at hand. The sun's rays do not burn until brought to a focus."

"What this power is I cannot say; all I know is that it exists and it becomes available only when a man is in that state of mind in which he knows exactly what he wants and is fully determined not to quit until he finds it."

"The nation that secures control of the air will ultimately control the world."

"The most successful men in the end are those whose success is the result of steady accretion."

"Neither the Army nor the Navy is of any protection, or very little protection, against aerial raids."

"America is a country of inventors, and the greatest of inventors are the newspaper men."

"Before anything else, preparation is the key to success."