(Corrects headline and first paragraph to clarify fleet is fully owned and paid for by the company)

Dec 6 (Reuters) - Canada’s WestJet Airlines Ltd said it expects to grow its number of aircraft fully owned and paid for by the company, as opposed to leased, to 96 by 2020 from 51 at the end of the third quarter.

WestJet’s new ultra-low-cost-carrier Swoop is expected to begin service in the summer of 2018, as other upstart carriers eye a similar time frame.

The company on its investor day said it is targeting an annual operating margin of between 10 percent and 12 percent in 2018 to 2020.