Smoking on board commercial aircraft was once quite fashionable, although no longer the case with present day European airlines. On a private jet however, it can be common.

The rules regarding smoking on private flights can vary depending on the specific policies of the operator, the country's aviation regulations, and the type of aircraft being used. However, in general:

• Commercial airline flights typically have strict no-smoking policies.
• Corporate or private flights may have more flexibility, and the decision can be at the discretion of the aircraft operator or commander, provided it does not violate any overarching aviation regulations or safety protocols.

CS 25.791 Passenger information signs and placards

(a) If smoking is to be prohibited, there must be at least one placard so stating that is legible to each person seated in the cabin. If smoking is to be allowed, and if the crew compartment is separated from the passenger compartment, there must be at least one sign notifying when smoking is prohibited. Signs, which notify when smoking is prohibited, must be installed so as to be operable from either pilot’s seat and, when illuminated, must be legible under all probable conditions of cabin illumination to each person seated in the cabin.

CAT.OP.MPA.240 Smoking on board

The commander shall not allow smoking on board:

(a) whenever considered necessary in the interest of safety;
(b) during refuelling and defuelling of the aircraft;
(c) while the aircraft is on the surface unless the operator has determined procedures to mitigate the risks during ground operations;
(d) outside designated smoking areas, in the aisle(s) and lavatory(ies);
(e) in cargo compartments and/or other areas where cargo is carried that is not stored in flame-resistant containers or covered by flame-resistant canvas; and
(f) in those areas of the passenger compartment where oxygen is being supplied.