If you're travelling into Canada by plane, sea or air, you will need a passport or a Western Hemisphere Travel Initiative (WHTI) compliant document. Not all WHTI-compliant documents can be used for air travel between Canada and the United States.
A passport card is a WHTI compliant document that you can order through the State Department. It's cheaper to get than a full passport book, and you can put it in your wallet. However, it can only be used for land or sea travel to Canada.
A NEXUS card is useful for frequent travelers between the U.S. and Canada; they are valid for land, air and sea travel. These cards allow travelers expedited passage through customs and border control, but applicants must interview and pay a fee.
If you live in Michigan, New York, Vermont and Washington, you can get an enhanced driver's license that will let you cross into Canada by land or sea. The license contains an RFID chip and barcode that can be easily scanned by border agents.
The FAST/Express Card is available for commercial truck drivers and permits easy land crossings between the U.S. and Canada.
