I'm still trying to imagine walking around with $40,000 in a suit case thinking **Please don't rob me, please don't rob me***
An additional issue being that it is illegal to fly with over $10,000USD within the United States. So yeah, meet at bank - withdraw - exchange is about the only semi-legal/safe way to conduct this. Of course some may not care about violating US law but having $38k seized is a fairly large risk IMHO
This is an urban myth
It is not illegal to fly with over $10,000 within the United States. That regulation only applies if you are traveling internationally, and in that case, all you have to do is declare it. So, it's not illegal.
Within the United States there is no regulation on how much cash you can carry when you are flying (or at any other time for that matter). Its still a free country in that sense.
http://airsafe.com/issues/baggage/cash.htm