UPDATE 1-Air Canada, WestJet post record numbers for September

* Air Canada load factor a record 84.9 pct, traffic up

* WestJet reports record load factors for September, Q3

* WestJet CEO says "demand remains healthy"

* Porter has decline in September, but sets Q3 record

(Adds Air Canada traffic data, analyst comments, stock prices)

Oct 3 (Reuters) - Canada's two largest airlines, Air Canada

and WestJet Airlines Ltd , flew with record levels of passengers for the month September, but levels at regional carrier Porter Airlines fell from a year earlier.

Air Canada, the country's biggest airline, said on Wednesday that its September load factor, or percentage of available seats filled with paying customers, rose 2.1 percentage points to a record 84.9 percent.

Traffic increased 3.1 percent as capacity, or available seat miles, rose just 0.5 percent.

"These strong results underscore the effectiveness of our disciplined capacity management," Chief Executive Calin Rovinescu said in a statement.

The load factor on Air Canada's flights to Australia, the Caribbean, Mexico, Central and South America made the biggest jump, to 82.9 percent from 79.4 percent in the same period last year.

For the third quarter, Air Canada said its load factor rose to 86.3 percent from 85.8 percent last year, as traffic rose 0.8 percent and capacity rose 0.2 percent.

Calgary-based WestJet, Canada's No. 2 carrier, said its September load factor exceeded its expectations, rising to a record 79.1 percent from 74.7 percent a year earlier.

Traffic was up 7.7 percent and capacity rose 1.7 percent in the month.

"The record load factor exceeded our expectations this quarter and demand remains healthy as we begin the transition into our winter schedule," WestJet Chief Executive Greg Saretsky said in a statement.

Based on the data, National Bank Financial analyst Cameron Doerksen raised his target for WestJet's stock price to C$23.50 from C$22, while lifting third-quarter and full-year 2013 earnings estimates.

"We believe these traffic numbers point to very good Q3 (third-quarter financial) results," Doerksen said in a research note.

"Furthermore, the company indicates that demand into Q4 (fourth quarter) remains healthy, which is confirmed by the continued strength we are seeing in our weekly airfare surveys so far in October."

Privately held Porter Airlines, a short-haul carrier, reported a load factor of 62.3 percent for September, down 5.7 points as much of its Labor Day traffic was counted in August because holiday fell earlier in the calendar than usual.

Even so, its third-quarter load factor of 69.1 percent was a company record for the quarter.

"We are also seeing higher average fares with the transition back to business travel in the fall season," Chief Executive Robert Deluce said in a statement.

WestJet shares rose 31 Canadian cents to end at C$17.71 on the Toronto Stock Exchange on Wednesday, while Air Canada shares added 7 Canadian cents to close at C$1.42.

($1=$0.99 Canadian)

(Reporting by S. John Tilak and Susan Taylor; Editing by Peter Galloway)

((john.tilak@thomsonreuters.com)(+1 416 687 7918))