Calgary-based WestJet reported an all-time record load factor of 88.9 per cent for August, up from 83.3 per cent a year ago.
The increase came as revenue passenger miles, or traffic, increased 9.2 per cent year over year, and capacity, measured in available seat miles, grew 2.3 per cent.
WestJet president and CEO Gregg Saretsky was pleased by the record load factor set while the airline flew nearly 172,000 more passengers in August compared with a year ago.
"The demand environment remains strong and we are seeing a growing contribution from our airline code-shares and interline partnerships," Saretsky said in a statement.
Earlier this year, WestJet announced a code-share agreement with South Korea's largest airline, Korean Air, and with China Eastern Airlines, one of the largest airlines in China.
Code share agreements allow travellers to more easily transfer from one airline's network to the other's. The deals came in addition to agreements with American Airlines, Cathay Pacific, Delta Air Lines, Japan Airlines, KLM and Korean Air.
Air Canada reported an August load factor of 87.9 per cent, up from 87.8 per cent in August 2011. Traffic increased 0.7 per cent as capacity increased 0.6 per cent.
"For the month of August, Air Canada reported an all-time record load factor," Air Canada president and chief executive Calin Rovinescu said.
"This record load factor result for the month underscores our disciplined capacity management and our industry-leading product that continues to earn our customers' loyalty."
The improvement at Air Canada came as the load factor on its domestic flights improved to 87.4 per cent from 86.2 per cent a year ago. U.S. flights saw an improvement to 82.6 per cent from 82.1 per cent.
National Bank Financial analyst Cameron Doerksen said the Canadian air travel market remains healthy.
"Clearly WestJet's August numbers point to a healthy demand environment," Doerksen wrote in a note to clients.
"WestJet’s numbers are boosted by the ongoing maturation of its code-share and interline partnerships, a trend that is set to continue through 2013 and beyond."
Meanwhile, Porter Airlines reported an August load factor of 74.5 per cent, up from 68.7 per cent a year ago.
Traffic on the regional carrier increased 21.4 per cent compared with a year ago, while capacity at Porter increased 12 per cent.
Shares in WestJet closed up 57 cents at $17.14 on the Toronto Stock Exchange on Thursday, while Air Canada's class B shares closed down a penny at $1.06.