WestJet Airlines Ltd. (TSX:WJA) says its flights in August took off with the lowest percentage of empty seats in the airline's history.

The Calgary-based airline reported an all-time record load factor of 88.9 per cent for August, up from 83.3 per cent a year ago.

Revenue passenger miles, or traffic, increased 9.2 per cent year over year, while capacity, measured in available seat miles, grew 2.3 per cent.

WestJet president and CEO Gregg Saretsky says demand remains strong and the airline is seeing growing contribution from its code-share and interline partners.

The airline said it flew nearly 172,000 more passengers in August compared with a year ago.

Meanwhile, Porter Airlines reported an August load factor of 74.5 per cent, up from 68.7 per cent a year ago.