More people flew WestJet than a year ago but because of an increase in seat capacity, the airline's load factor decreased slightly. (Larry MacDougal/Canadian Press)

WestJet Airlines Ltd.'s load factor dipped to 82.3 per cent in April even as the company flew a record 1.6 million passengers during the month.

The passenger figure was up 7.7 per cent compared to the same month last year and works out to an increase of about 116,000 passengers. 

But the airline's load factor — a closely watched airline metric that roughly equates to how full the company's planes are — dropped slightly because of an increase in capacity.

WestJet's passenger traffic increased 6.5 per cent year-over-year. Capacity grew 7.1 per cent year-over-year to 2.15 billion available seat miles.

The load factor figure was slightly below the 82.7 per cent recorded in the same month last year.

WestJet releases its first-quarter financial results on Tuesday.

The airline has said half the anticipated growth this year will come from its Encore regional service.

WestJet expects to take delivery of eight Q400s this year, doubling its fleet to 16 as it expands service from Toronto.