FILE PHOTO: A WestJet Boeing 737-700 takes off at the International Airport in Calgary, Alberta, May 3, 2011. REUTERS/Todd Korol/File Photo

(Reuters) - WestJet Airlines Ltd's WJA.TO joint venture with Delta Air Lines Inc DAL.N will put the Canadian air carrier in a stronger position to gain market share, credit rating agency Moody's Investors Service said.

WestJet on Wednesday announced the Delta joint venture to boost its trans-border flight service and said it expects to nearly double the number of aircraft owned by the carrier by 2020 as it targets both cost-conscious passengers and higher-paying customers.

WestJet’s decision is credit positive for unsecured debt holders. However, it faces execution risk in carrying out large scale projects simultaneously, Moody’s said in a note published on Thursday.

Shares of Canada’s second-largest air carrier were up 0.8 percent on Friday.