Passport Book vs. Passport Card
Passport Book
A passport book (commonly called a passport), is used for travel anywhere in the world by air, land sea; any 
mode of transportation. You are not limited to how or where you travel if you obtain a passport book. Adult passports are valid for 10 years; child passports are valid for 5 years. The U.S Department of State charges $170 for an expedited adult passport, and $140 for an expedited child passport.
Passport Card
A passport card is the size of a driver’s license and can be used ONLY for travel by land or sea to Canada, Mexico, Bermuda, and parts of the Caribbean. You cannot use a passport card for international travel by plane ever. This means you cannot fly to Canada, Mexico, or the Caribbean with a passport card. Adult passport cards are valid for 10 years; child passport cards are valid for 5 years. The U.S Department of State charges $90 for an expedited adult passport card, and $75 for an expedited child passport card. If you are considering flying to another country in the next 10 years, we recommend that you obtain a passport book and not a passport card.