What plane dropped the first Atomic bomb.

The plane that dropped the first atomic bomb was Enola Gay, the B-29bomber that was used by the United States on August 6, 1945, to drop an atomic bomb on Hiroshima

This is further explained below.

What is atomic bomb?

Generally, Fission reactions are the source of the energy that is used in the detonation of atomic bombs. The combination of nuclear fission and nuclear fusion is what makes thermonuclear weapons, often known as hydrogen bombs, possible. Another sort of reaction, known as nuclear fusion, occurs when two atoms of a lighter element unite to release energy.

In conclusion, The Enola Gay, a B-29bomber, was the aircraft used by the United States to deliver the first atomic bomb on Hiroshima on August 6, 1945.