VANCOUVER, British Columbia, Oct. 7 (Reuters) – Canada's two biggest airlines painted a mixed picture as No. 2 WestJet Airlines Ltd. said its planes flew fuller in September, while bigger rival Air Canada said it's were slightly emptier.

Air Canada said its consolidated load factor, or the percentage of available seats that are filled with paying passengers, fell to 79.7 percent last month from 79.9 percent in September last year.

Consolidated figures include data from Jazz Air, Air Canada's regional feeder airline.

System traffic, which measures demand for air travel, fell 2.1 percent even as the airline cut its capacity by 2.0 percent system-wide, Air Canada said.

''This result is in line with last year's record-setting load factor for the month and is attributable to our ongoing disciplined approach to capacity management,'' Calin Rovinescu, Air Canada's president and chief executive, said in a statement.

No frills airline WestJet said its load factor rose to 77.7 percent in September from 75.5 percent a year earlier. It cut capacity by 2.5 percent.

WestJet's traffic figures rose 0.4 percent to 1.07 billion revenue passenger miles, the first time since April that its year-over-year traffic data actually increased, according to airline analyst Cameron Doerksen.

WestJet, which has been one of the few profitable airlines in North America during a worldwide downturn in air travel, forecast a 15 percent to 17 percent decline in revenue per available seat mile in the third quarter.