I regularly travel from Canada to the US by bus and get a US Visa Waiver attached to my passport, which I hand back to the Canadian customs officer when returning to Canada (by bus).
This time I entered the US by bus as usual, but left the country by airplane. When I tried to surrender the visa waiver to the Canadian customs officer upon arrival at the airport in Canada, he informed me he had never seen this before, and did not take the waiver out.
I understand that usually when flying to/from the US these records are handled through ESTA. Does that mean there is a valid record of me leaving the US, and that I can take out the waiver myself? Are there any additional steps I should be taking?