WestJet continued to fill seats in record numbers in September, rounding a quarter that saw improvement every month, the Calgary-based airline said Wednesday.

"Guests are flying with us in record numbers, . . ." WestJet president and CEO Gregg Saretsky said as the airline reported a load factor of 79.1 per cent in September.

That was up from a load factor of 74.7 per cent in September 2011, even as capacity increased 1.7 per cent.

"We reported a record load factor each month this quarter which has translated to our highest ever quarterly load factor," he said.

Saretsky said the results exceeded expectations, adding that "demand remains healthy as we begin the transition into our winter schedule."

WestJet, which offers service to 81 destinations in North America, Central America and the Caribbean, said it flew 4.6 million passengers in the third quarter, a 9.7 per cent year-over-year increase.

Porter flies 62.3% full

Meanwhile, Porter Airlines saw its load factor drop in September as the number of passengers it carried slipped from a year ago.

Toronto-based Porter, which attributed part of the difference to a significant portion of Labour Day traffic flying in August due to the early holiday, reported a 62.3 per cent load factor for September, down from 68 per cent a year ago.

The drop came as capacity at the airline increased 6.7 per cent from a year ago and traffic fell 2.3 per cent.

"Overall, we're encouraged by the entire third-quarter results," Porter chief executive Robert Deluce said in a statement, however.

"We are also seeing higher average fares with the transition back to business travel in the fall season."

Based at Toronto's Billy Bishop Toronto City Airport, Porter flies to cities in Ontario, Quebec and Atlantic Canada as well as a handful of destinations in the United States.