The Calgary-based airline's planes flew 79.7 per cent full in the month, down 2.9 points from the same month last year, but up from 79.2 per cent in October.
Traffic measured in revenue passenger miles increased 5.7 per cent, on a 9.4-per-cent increase in capacity. The carrier flew 1.4 million passengers, up 3.8 per cent from the prior year.
"We are very pleased with the achievement of our second-highest November load factor, two percentage points better than our third highest, as our strong traffic growth continued in the month," said president and CEO Gregg Saretsky.
WestJet's Encore regional service has added Terrace, B.C., to its growing list of destinations. It plans to launch Encore in Toronto next summer.
Meanwhile, Air Canada (TSX:AC.B) said its November load factor fell to 76.5 per cent from 78.1 per cent a year ago.
The drop came as the airline increased system-wide capacity by 3.3 per cent, while system traffic increased 1.1 per cent.
"Major market segments, notably the U.S. transborder and Latin America and the Caribbean, experienced traffic growth in a month that is typically challenging for international carriers," Air Canada president and chief executive Calin Rovinescu said.
"Capacity added during the month was largely at significantly lower incremental cost due to the deployment of our high-density Boeing 777s and Air Canada rouge aircraft reconfigured with more seats."
WestJet (TSX:WJA) expects its capacity — as measured by available seat miles — will grow by seven per cent in December, eight per cent in the fourth quarter and 8.5 per cent for the full year.
In 2014, system-wide capacity is expected to grow by four to six per cent, with WestJet Encore representing about half that growth.
Despite the lower load factor, which measures the percentage of its planes filled with paying passengers, analysts said the robust November traffic numbers point to a continued healthy market.
"New capacity is clearly stimulating new demand, in particular on the domestic front as WestJet rolls out their new regional low cost subsidiary, Encore," said analyst Walter Spracklin of RBC Capital Markets.
"The key here is that while system-wide load factor compressed for the month, it remains healthy at levels close to 80 per cent and was on the back of a firmer pricing environment."
However, analyst David Tyerman of Canaccord Genuity said the lower load factor could feed investor anxiety that WestJet is trying to add too much capacity into the market.
"We think the results are better than the headlines suggest," he said.
Tyerman expects WestJet has good earnings growth potential from the launch of premium economy seating that should add about $80 million in annual revenues. He also pointed to WestJet Encore, that should add 50 cents per share in earnings by 2018, U.S. and international growth and the benefits from cutting $100 million of costs.
Air Canada also announced Wednesday it will fly its new Boeing 787 Dreamliners between Toronto and Tel Aviv, beginning in July.
The airline plans to preview the new aircraft on select domestic and transatlantic routes temporarily once the first three planes are delivered next spring.
Air Canada has ordered 37 of the planes which should be delivered by the end of 2019. The order includes 15 smaller 787-8 versions and 22 larger capacity 787-9s that should begin to enter the fleet in July 2015.
As it takes delivery of the aircraft, the airline plans to transfer older Boeing 767s and Airbus A319s to its low-cost subsidiary Air Canada rouge.
On the Toronto Stock Exchange, WestJet's shares were unchanged at $28.11 in Wednesday. Air Canada's shares hit a 5 1/2-year high, closing at $8, up 27 cents or 3.5 per cent.