Then people can decide whether to enter on those terms. If there weren't laws against smoking I'd have no choice. There are roughly 40 million smokers leaving well over 200 million American nonsmokers. Northwest Airlines, for example, banned smoking on their flights before it was the law. Some other airlines might have suit.
Business executives are cowards in many respects.
That's why airline executives yielded to the smoking ban on domestic flights. They would have fought had Congress extended the ban to international flights. But they should have known that cigarette prohibitionists wouldn't be satisfied. Recently, eight of the world's largest airlines joined together seeking immunity from antitrust laws in order to form a collusive arrangement to ban smoking on international flights. On January 24th, Department of Transportation secretary Federico Pena granted them immunity.