Peak Season:
The peak season in Canada all depends on your reason for going. If you're a fan of Winter sports, then between November and March offer the best chances of snowfall. Cheap flights to Canada are best found at this time so long as a big festival isn't taking place. May to September can be a great time to book your flights to Canada if you want to experience the best weather, especially if you're a fan of camping, visiting the national parks or visiting the beaches of British Columbia. If you are planning your flights to Canada to coincide with a festival, make sure to book well in advance for savings on your flight tickets.
Off Season:
Winter is the best time to grab cheap flights to Canada, although the weather can be unbearable for people who aren't keen on very low temperatures and lots of snow. The winter season is very developed though, with fantastic skiing and snowboarding facilities available, you can also find yourself ice-fishing or dog-sledding. If you can't handle the cold well then definitely avoid booking flights to Canada between November and February.
The cheapest flights to Canada are available between May and June, although this depends somewhat on where you're flying to. There are a lot of festivals and events in Toronto for example between June and October, so this will make it a lot more expensive to purchase your flight tickets. Do research into the country you want to fly to and figure out what, if any, festivals are on during the time you want to visit before your book your flights to Canada. If you can be flexible with your dates, you'll have the best chance of finding deals on your flight tickets. You can also find cheap flights to Canada if you book at least 1 or 2 months in advance. If you're flying to Toronto, sit on the right hand side to have a chance of the best views as you approach, Vancouver can vary depending in weather and what runway you land on but generally the right hand side can offer you a view of Mt.Baker.
Flights from London (All airports) to Toronto - 7 hours 50 minutes
Flights from Manchester to Vancouver - 11 hours 00 minutes
Flights from Birmingham to Montreal - 10 hours 35 minutes
Flights from Glasgow to Toronto - 10 hours 20 minutes
Air Canada, Iberia and British Airways and Air Transat are 4 of many airlines that operate flights to Canada. Depending where in Canada you wish to travel, you'll find slight variations in price although don't expect one airline to be dramatically different than another one. Your best option once you've decided on a location is compare the airlines and see what extra benefits they offer before securing your flights to Canada.
Toronto:
The best way to immerse yourself into the local lifestyle is the jump on the 'Rocket'. It'll take you directly from the airport to Kipling Subway Station where you can ride the subway anywhere you want to go. You can also take a coach which is more expensive but less hassle than the rocket. Lastly you can take a taxi, however these are very expensive and if you're not careful you'll end up with no spending money left for your holiday.
Montreal:
You can catch a taxi from straight outside of the airport at a fixed price of $40 to downtown. Tips of between 10%-20% are expected so make sure to add this onto the fare. If there are 2 or 3 of you this can work out quite cheap if the cost is split between you. Another option is the 747 express bus which takes around 45 minutes and has onboard WiFi. Public buses are available too however there are time consuming and you can only pay with coins. If you have a lot of luggage they can be quite a bit of hassle too, so it's advisable to either get a taxi or the 747 express.
Vancouver:
The best transport option available is the Vancouver Line which connects the terminals to downtown in around 25 minutes. It's an efficient and convenient method and great if you have luggage with you. Depending on your hotel, you might also be able to get a courtesy shuttle from the airport. You can use a special phone after your flights to Canada and arrange for them to pick you up. It's best checking with the hotel beforehand to see if they offer this service though.