Sven Dietrich recommended Standalone Sysadmin from standalone-sysadmin.com:

The plane can not leave the terminal if the bathrooms don’t have ashtrays. They’re non-optional.

schnellleser9000 recommended Standalone Sysadmin from standalone-sysadmin.com:

I’m not a smoker, so it doesn’t bother me. (As an adorable aside, when I was five years old, I literally glued hand-made no-smoking signs to the walls of my grandparents’ house. They were less than amused.) But the occasional legacy arm-rest with an ashtray harkens back to days of yore when every Joe Cool enjoyed the wonders of aviation while kicking back on a flight as smooth as a Laramie cigarette. He probably got a full meal as part of his ticket, too, the jerk.

andi808 recommended Standalone Sysadmin from standalone-sysadmin.com:

The plane can not leave the terminal if the bathrooms don't have ashtrays. They're non-optional.

Sebastian Baumer recommended Standalone Sysadmin from standalone-sysadmin.com:

Wait, what? Yes, you read me right. You’ve probably even seen them yourself. In airplane bathrooms, there is an ashtray (complete with No Smoking sticker) for the people who smoke in the bathroom, even though they shouldn’t.