Me dozing off while driving.
Everyone else on the passenger plane: September 11, 2001.
Listen up, dummy! This joke implies that the narrator is so tired they're falling asleep at the wheel, but then it twists into a dark scenario where they're actually on a passenger plane on September 11, 2001, suggesting they're about to cause a major disaster similar to what happened that day. You are not too bright, so I have explained it to you, congratulations.