My Canadian friend is wanting to get a passport card instead of a book, because they're cheaper, and we're curious about the limits of the card after she crosses over from BC to Washington. I've a card myself, and am flying from Burbank, CA to Sea/Tac in a week, then taking a bus to Vancouver, BC. However, we're wondering if either of us will be able to use the airports of the others country after crossing, or is it still limited to just taking a boat, car, bus, and/or train?