KLM is in Terminal 3 at Pearson. Airlines always suggest checking in for international flights 3 hours prior to departure. However, you can (with some airlines) check in 24 hours before your departure online. Then just check-in at the kiosks to get your baggage tag. The parking by the monorails is Viscount Parking - they have a lot as well as a garage (covered - or most of it). And getting from the parking to the terminal is via the Link train. If you don't have an assigned seat, best go when the counter check in opens (they must be open 3 hours prior to each flight) - else, you can probably check in 2 hours before - but evenings ar busy at Pearson and you don't want to get stuck in a security line up. Just my thoughts - hope they are helpful