* WestJet Load factor down 3.6 points

* Air Canada down 1.3 points

* WestJet uses some cash to buy out aircraft lease (Adds Air Canada load data)

VANCOUVER, British Columbia, July 6 (Reuters) - Canada's two largest airlines, WestJet Airlines Ltd (WJA.TO: Quote, Profile, Research) and Air Canada (ACa.TO: Quote, Profile, Research) said on Monday their planes flew less full in June amid a recession-driven slowdown in air travel.

WestJet said its load factor, the percentage of available seats that are filled with paying passengers, fell to 72.9 percent in June from 76.5 percent in the same month last year.

Demand for air travel, measured in revenue passenger miles, decreased 7.1 percent year-over-year to 1.03 billion, while capacity, measured in available seat miles, declined 2.5 percent over the same period to 1.41 billion.

"We anticipate second-quarter revenue per available seat mile to be in line with our original expectations of a second-quarter year-over-year decline of 16 to 18 per cent," WestJet President and Chief Executive Sean Durfy said.

Air Canada, the No. 1 carrier, said its load factor of 80.9 percent on a consolidated basis with its Jazz regional unit was down from the 82.2 percent it had a year ago. Load on mainline flights was 82.2 percent compared with 83.1 percent in June 2008.

System traffic decreased 9.1 percent on a capacity reduction of 7.6 percent system wide, Air Canada said.