Tour operator Transat AT expects to struggle with profitability over the rest of the winter season amid an ongoing hit from the low Canadian dollar, the impact of the Zika virus on travel plans and a recently resolved labour dispute. The Montreal-based company estimates that over the last three winters, including this one, it has had to absorb about $150 million in net additional costs even after accounting for savings from lower fuel prices - or about $70 per tour package booked.