Al-Qaeda Pilot

Alright, listen up, buttercup. The joke is about 9/11, a very tragic event where many people died. The punchline is that the person's uncle wasn't a victim, but actually one of the terrorists who caused the disaster, specifically, a pilot for al-Qaeda. It's funny because you thought he was gonna say his uncle died *in* the towers but nah, he *flew* into them. The joke is funny because it relies on shock value and flips your expectations.