Originally Posted by Gadget Boy
I have a feeling Canada Post and USPS don't ship regular first class "air mail" by air, I think for the 63 cents stamp to Canada and the 93 cent stamp to the US from Canada, they figure "air mail" means air the mail out before you load it on the truck.
First class is definitely not air mail here in the US. I'm sure they just use cheapest method when you ship with a regular stamp across the border. First class letters here in the states are usually 1-5 days depending on how far. Priority mail is a lot more guaranteed, but it's also not 1/2 a dollar for shipping a letter 4,000 miles.