> I kinda wish the airlines would have a dress code

I'd take a code of conduct before the dress code. Though, appropriately enough, I suppose the latter signals the former

Decent people don't need a code of conduct.

There's been pressure on the D Language Foundation to have a CoC. I've consistently refused one. The only thing I demand is "professional conduct". Sometimes people ask me what professional conduct is. I reply with:

1. ask your mother

2. failing that, I recommend Emily Post's book on Business Etiquette.

And an amazing thing happened. Everyone in the D forums behaves professionally. Every once in a while someone new will test this, their posts get deleted, and then they leave or behave professionally.

I meant for flights (edited accordingly). In both cases I think "don't be a dick" probably would go most of the way

You'll get treated better by the staff if you dress better.