First…. Fort McMurray has limited competition for flights so ‘cheap flights’ has a limiting factor as to how low they go. That being said there are days when flights are cheaper.
You can use calendar display and airline display to help you decide the best options.
First choose the day you would like to travel and then ask the 3 day calendar for flights 3 days before or 3 days after the date you choose.
In this example the flights on the weekend days were cheaper than week days and flights on Thursday was the most expensive day to fly.
The competition may be cheaper on some days but may require extra stops. So the quickly see the best options is to group flights by the airlines using an ‘airline view’ to visualise the offerings.
In this example only one airline flys non-stop and the alternative airline is only $1.00 different in price… Still one way looks good with 2 options on the day.