There are lots of ways to get here 

. . . but mostly there are two.

If you are flying from New York, DC, Chicago or Montreal, consider flying Porter. You avoid Pearson, a giant airport far from the wedding. Porter frequently has sales, so you should probably wait for one. There is a free shuttle bus to downtown and you can get cabs pretty easily.

Otherwise, you can book via kayak. You will probably end up landing at Pearson, it will cost you $27 by bus and $60 by cab to get downtown. You can Uber, too.