(Adds details on Saretsky's tenure, background on company's strategy)
March 8 (Reuters) - WestJet Airlines Ltd said Chief Executive Gregg Saretsky is retiring immediately and would be succeeded by executive vice-president Ed Sims.
The Canadian commercial airliner said on Thursday that Sims has more than 30 years of experience in the tourism and aviation industry.
WestJet's shares have risen about 64 percent since Saretsky took the top job in March 2010, as the company doubled its fleet and offered more services such as WestJet Encore and rewards programs that attracted more customers.
Saretsky focused on evolving Canada's second-largest carrier from a single brand into a multi-brand service including its ultra-low-cost carrier Swoop, which is due to be launched in June.
Reporting by Karan Nagarkatti in Bengaluru; Editing by Sriraj Kalluvila