Why do airlines not id for alcohol?

Question

While I'm very much so old enough to drink, I look younger than I am and I regularly get carded when I buy any sort of alcohol, be it from a liquor store, restaurant, etc. But I have never once been asked for ID on an airplane. I thought at first the manifest might have the age of people traveling but I have had several underage friends successfully order alcohol on airplanes before.

Answer 1

It's been my experience that on domestic flights within the US it's much more likely that someone will get carded than on international flights - especially on foreign carriers.

I don't know that it's a matter of airlines not checking for passengers' ID so much as it not being a high priority for flight attendants.  Also, on a foreign-flagged carrier the drinking age of that country becomes the drinking age on the plane, so that may also be a factor.