Is this guy not thinking?! JB knew before he took off for New Jersey that his plane would get searched by U.S. Customs yet he and his entourage still hotboxed on the private jet. The pilot radioed in the air Justin and his people were smoking marijuana on the jet and the flight stewardess couldn’t stop them. The pilot complained the smoke in the cabin was thick. NBC News says the pilot actually had to don a gas mask because it was so bad. But strangest part is, Justin is on a Homeland Security watch list because of 2 pending criminal cases. Multiple sources connected with Bieber tell TMZ … “Justin’s people called federal officials before the plane took off and they were informed Justin was on the list. Justin’s people told him before he got on the jet that he would be searched in New Jersey and interrogated, yet Bieber STILL smoked up the aircraft.” Bieber and his buds were “abusive” to the flight attendant because she asked them to stop smoking. Best part? Bieber’s father was on the plane. By the time the plane got to NJ the mary jane was gone, but drug-sniffing dogs detected trace amounts. A person on the aircraft said that 3 hours after it landed it continued to smell like marijuana.