[AYoung010]

I’ve heard that the continued presence of ashtrays isn’t a vestigial design feature so much as an intentional holdover, so that anyone who breaks the “no smoking” rule still has a safe place to put out their cigarette.

[bombcar]

That's for the ashtrays in the bathroom, which can still be found on the newest jets.

[NoZebra120vClip]

And that's probably why they need to constantly remind all the passengers that there is no smoking in the bathroom, and please don't tamper with the smoke detectors in there, we really mean it, please ignore the emergency-use ashtrays.