Mr. Speaker, pre-clearance will benefit those who travel outside of Canada. Pearson airport only has a facility to land. Certain airports in the U.S.A. have customs and immigration services. However, if those services are not available in airports where people will land, they can go through pre-clearance before leaving and can land at U.S. airports as domestic passengers, which will be beneficial to them.
In the House of Commons on February 24th, 2017. See this statement in context.