The Sky Jack was a plane sent to drop a third atomic bomb on Kyoto, Japan in World War II in 1945. Before it delivered its payload, it fell through a black hole into the Eleventh Doctor's TARDIS. (COMIC: Sky Jacks)

On 5 August, the Sky Jack took off from Iwo Jima and headed northwards towards Japan on a top secret mission to drop Big Momma on Kyoto. Despite the secrecy, the Sky Jack was spotted by Japanese Zeros and attacked. All but three members of the crew were killed and the aircraft began rapidly losing fuel at a rate which meant it was not possible to reach Kyoto. The crew's only hope of survival was to reach the Ogasawara Islands but doing so risked the Japanese discovering the existence of the atomic bomb and potentially capturing it for their own use. Captain Filmore ordered the pay load to be dropped into the ocean and hoped that the other two bombs would be more successful. Before the crew could dispense with the bomb, the Sky Jack suddenly fell into a black hole, where the crew spent three years before the Eleventh Doctor returned them home. Kyoto was spared and the details of Big Momma and the bomb run would remain a secret. (COMIC: Sky Jacks)