Originally Posted by
BAAZ
Same for me; I drove from US to Canada and didn't surrender the I-94W stub in the passport. On driving back into the US a few days later, the stub was enough to let me through and I didn't need to fill in any more forms.
That's definitely the right thing to do if you will be returning to the US from Canada/Mexico etc within 90 days, but if heading back to Europe you need to hand it in somewhere. Good to know that this can be done at a Canadian airport as well as at the border!