* WestJet reports fourth month of record levels
* Forward bookings remain healthy, WestJet CEO says
* Porter says load factor down due to its focus on yield
TORONTO, Nov 5 (Reuters) - WestJet Airlines Inc flew with record-setting passenger levels in October for the fourth straight month, Canada's second-biggest carrier said on Monday.
WestJet's October load factor, or percentage of available seats filled with paying customers, rose to 81.2 percent from 77.4 percent a year earlier.
Traffic increased 5.9 percent as capacity, measured in available seat miles, rose just 0.9 percent.
"Forward bookings remain healthy and momentum continues at WestJet," said Chief Executive Gregg Saretsky.
Shares of the airline, which reports third-quarter financial results on Wednesday, rose 1.3 percent to C$18.04 on the Toronto Stock Exchange in early trade.
Year-to-date, WestJet's load factor has climbed to 82.9 percent from 79.8 percent in the same period last year. Traffic is up 8.2 percent, while capacity is 4.2 percent higher.
Traffic data is expected later on Monday from Air Canada , the country's largest airline.
Privately held Porter Airlines, a smaller short-haul carrier, reported a load factor of 59.4 percent for October, down from 67.7 percent for the same period last year.
Traffic declined 7.5 percent, while capacity rose 5.5 percent.
"We are currently focusing on maintaining higher yields, so the change in load factor is expected with this approach," said Chief Executive Robert Deluce.