When traveling on a domestic flight within the United States, there are no limits to how much cash you can carry. A large wad of cash may attract questions from the Transport Security Administration (TSA) at the passenger screening area, but a quick proof of ownership may be sufficient to let you off the legal hook.
Each country you visit has regulations regarding how much cash travelers can bring in and take out. There are no restrictions if you are coming in or going out of the United States, but you must declare how much cash you are flying with to the CBP if it exceeds $10,000 in cash.
Single Market Economy reports that Canada and Mexico are the top destinations for US resident travelers, followed by the United Kingdom, Italy, and France.
The Bureau of Transportation Statistics also reports that Canada, Mexico, the United Kingdom, Japan, and China, in that order, top the ranks of nationalities that have traveled to the US.
A cross-section of inbound and outbound flights from and to the United States shows that European countries such as the United Kingdom, Italy, and France share the most travelers after North American countries of Canada and Mexico.