It’s probably the most asked question when it comes to travel: Is there a best time to book a trip? The short answer is yes, but it varies by destination. The travel search engine KAYAK looked at the median cost of flights from Canada and the US to ten luxury destinations to see how the airfare varied from one to six months prior to departure. The results show that if you really want to find the best time to buy, you’ve got to do your homework. Airfares are quoted in US dollars.