Unfortunately, Air Transat (and CBSA and luggage handlers) doesn't work closely with Via to coordinate schedules. I often rent a car to get from YUL to home in Ottawa; it's predictable and, until this year, not too expensive. I'm on a YUL/LGW Air Transat return over the period 12 Aug - 2 Sept and it is much cheaper for me to take the bus from Ottawa Station to the airport and rent a car to come home than drive and park. Via is not very much less expensive but has some built-in hassles, delays and scheduling uncertainties. I'm willing to do this because the airfare was less than half what Air Canada wanted for London/Ottawa return in Premium.