So I went back to America from Thailand recently with a small amount of weed. Went from BKK to short stopover in Doha to Boston, MA. It's legal in MA. I'm not suggesting anyone do this, it's prohibited to fly with it and it's not legal in doha.
There's no signs at BKK Airport about weed, at least I never saw any. I had it in my carry on. In doha, I had to go through security twice. I was the most nervous about it here, for good reason. Other than that, it was smooth sailing.