I live in Detroit and I’m flying into Toronto from an international destination. My last leg of the journey is from Toronto to Chicago. Instead of taking the last leg of the journey, can I exit the Toronto airport after completing Canadian immigration/customs and drive to Detroit? I save a ton of time. Thanks
can I exit the Toronto airport?
Two things to consider. This will violate the terms and conditions of your ticket. Since it's your last leg, the airline cannot easily retaliate by cancelling your other leg, but they may ding your status, revoke miles etc. In rare cases the airline has actually sued a passenger but so far without success.
Read up on "hidden city ticketing" for more information.
The second thing to watch out for is that Toronto has US pre-clearance. That implies that your bags will be checked through to the US and not unloaded in YYZ. I'm not entirely sure whether you officially enter Canada for International->US connection in a pre-clearance airport. The airlines typically provide passenger lists to immigration. You getting off in Toronto may create discrepancies between what these lists and what actually happened. I have no idea whether this is a potential problem or not.
The airline doesn't like when you do this because of Hidden City Ticketing. They will cancel the rest of the trip (if you have a return ticket, that will also be cancelled). You may suffer more consequences if you do this regularly, like cancellation of frequent flyer program, etc and even a ban.
One thing you might want to consider is calling the airline and asking if you can change the flight to stop in Toronto. In particular, if you are flying Air Canada for example (if that's why you flew through Toronto), the odds are the Toronto flight is much cheaper than the Chicago flight - for example, LHR-YYZ is much cheaper than LHR-YYZ-ORD, less than half the price. Obviously last minute it's more expensive, but it's possible they'd prefer to sell the YYZ-ORD flight to someone else.