"Hap" Arnold is primarily remembered by fans of the P‑38 as the man who approved its first, historic cross-country flight to New York. You can read more about this attempt (and the results of that flight) here.
It met an rather inglorious end due to an icing problem, but based on the success of that flight, the USAAC ordered its first round of P‑38s to be built.
If you'll notice is date of birth in the right-hand column, you may not be surprised to learn that he was taught how to fly by the Wright Bros.
When he noticed the severe shortage that America had of trained combat pilots, he approved a plan (submitted by Jacqueline Cochran) to train female pilots as ferrying pilots within the U.S. to fly aircraft wherever they were needed within our borders.
Although it failed to pass, Arnold prevailed upon Congress to pass a bill to make these female pilots commissioned as officers in what had become the Army Air Force.
As a result of that early plan (submitted by Jacqueline Cochran), Aug 20, General Arnold, CG/AAF issued orders that " The acronym for all AAF women pilots will be WASP (Women Airforce Service Pilots) period."
"Hap" Arnold was a man of many names, including:
Harley - by his family during his youth.
"Sunny" - by both his mother and wife.
"Pewt" -- by his West Point classmates.
"Benny" -- also by his West Point classmates.
"The Chief" -- by his immediate subordinates and headquarters staff.
But he will forever be known as "the father of the U.S. Air Force" because his vision of airpower established U.S. air supremacy during WWII and laid the foundations of today's Air Force.