Bill Wilson was the CIA operative in charge of capturing Dr. Leonid Pavel from Uzbekistan. These plans were cut short, when he was murdered by Bane and his League of Shadows remnants.
"If I pull that off, will you die?" "It would be extremely painful." "You're a big guy!" "For you."
―Wilson and Bane's exchange minutes before the plane crash[src]
Eight years after the death of Harvey Dent, mercenaries posing as a local militia, headed by one Barsad, turned over the Russian nuclear physicist Dr. Leonid Pavel to a group of CIA paramilitary officers and flight crew in Uzbekistan. Bill Wilson was the CIA officer appointed to supervise the operation. In addition to Pavel, Barsad gave him three hooded prisoners whom he claimed were working for the "masked man" and had attempted to capture Pavel, but were in fact Bane himself and two of his hired guns.
Bane's plan was to find out how much Pavel had told the CIA about them and to fake the scientist's death while on board their flight and then crash the plane with no survivors. To that end a plane full of mercenaries secretly tailed the CIA plane whilst airborne.
Wilson tried to interrogate his prisoners about Bane, by pretending to shoot whoever remained silent before throwing them out of the plane so that they would be intimidated, but he was unsuccessful. Bane revealed his presence, and pointed out that their attempts wouldn't work because the hooded men had no reason to give in when the CIA officer was only putting on a show. He also told Wilson of his plan as the officer removed Bane's hood, knowing that they would not survive the attack, and broke free of the restraints just as more of the mercenaries arrived from the other plane to shoot the CIA personnel. In addition, the mercenaries brought in a cadaver to transfer Pavel's blood to fake the latter's death. Bane proceeded to attack Wilson, and left him on board the plane as it fell to the ground, most likely killing him.
Trivia
In the film, he is listed as CIA Op and introduces himself to Dr. Pavel simply as "CIA", and is otherwise unnamed. The novelization written by Greg Cox reveals his name to be Bill Wilson. The book later refers to him as "nameless operative", which might indicate that Bill Wilson is a codename.
The novel reveals that Wilson's main motivation to capture Bane was to obtain a promotion in the Agency.
Bill's alternative death.
In the comics, Bill has a very different death where holds him and snaps his neck swiftly.
In the novel, the location of the scene where Wilson picks up Dr. Pavel, the location is mentioned as "Somewhere in Eastern Europe", while in the film it is given as Uzbekistan.
Bill clearly had blanks loaded in his pistol while acting as if he was shooting the prisoners, as the slide on his gun does not recoil like a live round would've made it.
Along with Bane, Wilson is the subject of an Internet meme called "Baneposting", the act of mentioning several references and parodying the awkward dialogue during the plane scene. The meme was widely spread on the website 4chan.
