From the press release:
WestJet today introduced Kargo Kids, an exciting new program allowing guests to travel on select child-free flights, creating a quieter and more relaxing inflight experience, while children travel in a "special VIP" area of the aircraft.
"As Canada's low-cost airline, we are constantly looking for innovative and fun ways to enhance the guest experience," continued Richard Bartrem. "The initial feedback on Kargo Kids has been quite positive and we're looking forward to the peace and quiet while we get families where they need to be."
Thanks to Kelly for the tip :)