Soundness of mind

Is it illegal to fly with large amounts of cash?

It is not illegal to fly with large amounts of cash, but it is strongly recommended that you declare any amount of cash over $10,000 to U.S. Customs and Border Protection. Failure to declare large amounts of cash may result in the money being seized, and you may face criminal charges. Additionally, some airlines have policies that limit the amount of cash passengers are allowed to bring on board.