Originally Posted by
Shareholder
BTW you will have to retrieve your bag at YYZ for US preclearance purposes, then recheck it onto you ATL flight.
OP, I cant tell you how much this requirement is a PITA! If you are on the 830a flight to ATL, even the 6a YOW-YYZ could be a rush.
It sucks going to USA via YYZ, it's 10X worse coming back to YOW via YYZ if you have to wait for checked luggage.
Good luck but I would strongly recommend via CLT/IAD from YOW if you can.