Under U.S. government rules, smoking is prohibited on all domestic scheduled-service flights except for flights over six hours to or from Alaska or Hawaii. This ban applies to domestic segments of international flights, on both U.S. and foreign airlines (e.g., the Chicago / New York leg of a flight that operates Chicago/ New York / London). The ban does not apply to nonstop international flights, even during the time that they are in U.S. airspace (e.g., a Chicago / London flight). The prohibition applies in the passenger cabin and lavatories, but not in the cockpit. Smoking is also banned on other scheduled-service flights by U.S. airlines that are operated with planes seating fewer than 30 passengers (e.g., certain "commuter" flights to Canada, Mexico and the Caribbean). Cigar and pipe smoking is banned on all U.S.-carrier flights (scheduled and charter, domestic and international). The following rules apply to U.S. airlines on flights where smoking is not banned (e.g. international flights, domestic charter flights). These regulations do not apply to foreign airlines; however, most of them provide non-smoking sections (although they may not guarantee seating there or expand the section).

* The airline must provide a seat in a non-smoking section to every passenger who asks for one, as long as the passenger complies with the carrier's seat assignment deadline and procedures. (Standby passengers do not have this right.)

* If necessary, the airline must expand the non- smoking section to accommodate the passengers described above.

* The airline does not have to provide a non-smoking seat of the passenger's choice. It doesn't have to seat you with your traveling companion, and you don't have the right to specify a window or aisle non-smoking seat. Also, the airline is not required by this rule to provide advance seat assignments before the flight date in the non-smoking section, as long as they get you into the non-smoking section on the day of your flight.

* The flight crew must act to keep passengers from smoking in the non-smoking sections. However, smoke that drifts from the smoking section into the non-smoking section does not constitute a violation.

* No smoking is allowed while an aircraft is on the ground or when the ventilation system is not fully functioning.

* Carriers are not required to have a smoking section. An airline is free to ban smoking on a particular flight, or on all of its flights.