Under FAA Part 91 regulations, which govern private, non-commercial flights, there is no explicit federal law that prohibits a pilot or passengers from smoking in a private aircraft. This is a stark contrast to commercial aviation (Part 121), where smoking has been banned for decades. However, the decision ultimately rests with the aircraft owner and the Pilot in Command (PIC), who has final authority over the safety of the flight. Most modern operators and owners prohibit smoking due to the high fire risk, the significant damage smoke causes to sensitive avionics, and the exorbitant cleaning fees required to remove odors. Furthermore, smoking is strictly forbidden during critical phases of flight, such as taxi, takeoff, and landing, whenever the "No Smoking" signs are illuminated. If you are chartering a jet, the contract almost certainly includes a no-smoking and no-vaping clause.