they were dropped from b29 bombers
The B-29 had a maxium speed of 357 MPH, and a cruising speed of 220 MPH. It had a combat range of 3,250 miles and could fly at 33,600 feet. It was armed with 12 .50 cal. machine guns (some had a 20 mm tail gun) and could carry 20,000 pounds of bombs. It had a crew of 11 men.
The atomic bombs were transported by ship to the island the B29's would launch from and were unloaded into a pseudo warehouse to keep them safe.
According to official records, about 2400 emergency landings were made on the island by B29's and presumably, by their P51 escort fighters.
the B29 normally carried a 11/12 man crew
While the B29 was expensive it cannot even compare to the real most expensive project of World War 2. The Manhattan Project was the most costly project to develop the atom bombs used in World Wa2. This project cost well over 2 Billion Dollars in the 1940s. That would be like a 20 Billion or so dollars today. So the atom bombs each cost slightly under a billion dollars a piece.
b29
boxcar b29
Ohio
That is an aircraft designed to transport nuclear bomb safely to the area to be dropped. The first nuclear capable aircraft used in history was a B29 bomber named Enola Gay which was modified to carry the nuclear artifact.
It was a B29 Super-fortress built by Boeing.
Enola gay.