If you smoke before, or worse, during a flight, you are destroying your performance due to hypoxia like phenomenons. The carbon monoxide hooks up with the hemoglobin with so much force, takin the place of the oxygen and staying there for hours.. .This has an effect that "climbs" your body to 6 to 8000 feet. WHen your airplane has a cabin altitude of 7 to 8OOO feet, because of your cigarette induced advance, your body is at 12 to 16 thousand. Hence the tremendous loss of performance.. .Obviously not a good idea and not acceptable.. .. .If one is medicaly "hooked" to nicotine, other problems occur. When beeing deprived of your legal drug, your performance decreases, among other reasons because of the increased nervosity and aggresivity caused by the craving.. .. .SO what can be done ?. .Short term solution : Use nicotine replacements that do not shoot you up with carbon monoxide before and during the flight.. .. .Long term solution : Get medical assistance to efficiently become unhooked of this legal drug.. .. .Ideas and infos: It is my understanding that some major European airlines will not offer you a job if you are a smoker. At the same time, they offer medicaly assisted programs to help their smoking crewmembers getting cured.. .In my small company, smoking on the job is ground for immediate dismissal.