Recreational Marijuana States. Four states, including Alaska, Oregon, Colorado, and Washington, as well as Washington D.C. have passed ballots legalizing recreational marijuana. The amount you can possess at one time, however, varies between the states.
As of January 31, 2014, passengers traveling internationally into the U.S. and connecting to another flight are allowed to have in their carry-on baggage liquids in excess of 3.4 ounces (100 mL) that were purchased as duty-free merchandise.
Current customs laws state no legal limit to the amount of currency you can carry on a plane while flying domestically. If you fly within a state or from one state to another, you face no cash restrictions, but TSA agents may ask questions about the source of your cash and the reasons you have it with you.