(Corrects last paragraph to show Air Canada stock closed at C$2.16, not C$44.47, on Friday)
June 6 (Reuters) - Air Canada ACa.TO, Canada's biggest airline, said it flew slightly fuller planes for May from a year earlier, while its nearest rival WestJet Airlines' planes were emptier.
Air Canada said its system load factor for May was 82.2 percent, up from 82 percent in May last year.
"Led by a 13 percent increase on U.S. transborder routes, we generated greater traffic in all markets with system wide growth of 5 percent," Air Canada Chief Executive Calin Rovinescu said in a statement.
WestJet CEO Gregg Saretsky said, "An increase in our domestic capacity this month contributed to a lower year-over-year load factor."
WestJet's load factor -- the percentage of available seats filled with paying customers -- fell to 74.8 percent from 77.7 percent in May last year.
For WestJet, revenue passenger miles, or traffic, rose 3.1 percent. Capacity, measured in available seat miles, grew 7 percent.
Shares of Calgary-based WestJet closed at C$15.25, while Air Canada shares closed at C$2.16 on Friday on the Toronto Stock Exchange. (Reporting by Bhaswati Mukhopadhyay in Bangalore; Editing by Don Sebastian)