As of now, 20 states have legalized marijuana for medical purposes, and voters in Colorado and Washington have approved marijuana for recreational use. About a dozen more states are expected to legalize marijuana in some form over the next several years.
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.
Remember, that to abide by the TSA rules for what can be packed in carry on luggage, each passenger may pack 3 ounce bottles or less, into 1 quart sized ziploc bag, and 1 bag is allowed per passenger. This is affectionately referred to as the 3-1-1 rule.