In 1940, against the advice of his agent who said "the big parts are coming", he hopped the S.S. Lurline (manifest records February 21, 1941) to Honolulu, Hawaii, where he learned to fly and made his first solo flight in 1941.

He was working at Pearl Harbor as a civilian digging underground fuel tanks on Sunday, December 7, 1941, when the base was attacked.

After witnessing the Japanese attack he immediately enlisted in the United States Army Air Forces.

"Jack" took flight instruction by Lt. F. D. Clasen in a Vultee BT-13 at Chico Army Air Field, class of '43-D squadron 2.

After his crew bailed out, he forced his way out of the nose door, dislocating and fracturing his shoulder and breaking his right arm in the process.

[3] Conroy remained on active duty with the USAAF until 1948, serving as a special air mission pilot and as an instructor in a reserve training unit.

He flew an F-86A Sabre from Van Nuys to Floyd Bennett Field, New York, and returned using fuel stops both ways, setting a record of 5058 miles in 11 hours, 26 minutes, 33 seconds (442.0 mph).

One evening Conroy, Lee Mansdorf and others were discussing the problems NASA were having transporting the rocket booster stages aboard ships through the Panama Canal and the Gulf of Mexico.

However the huge aircraft performed flawlessly, the only difference in handling being a slight decrease in speed caused by extra drag of the larger fuselage.

Wernher von Braun stated that "The Guppy was the single most important piece of equipment to put a man on the Moon in the decade of the 1960s."