TORONTO -- Air Canada's class B shares touched a fresh five-year high in heavy trading Wednesday, extending an upward trend that has seen the airline's stock value more than triple in the past year.

The shares (TSX:AC.B) traded for as much as $5.80 during the session, a level not seen since August 2008 -- just weeks before the economy slipped into a deep recession.

The shares were up 21 cents at $5.71 in afternoon trading.

A year ago, the stock closed at $1.80 on Oct. 30, 2012.

Since then, the company has launched Air Canada Rouge, a new discount carrier that began flying in July.

Air Canada's stock, which had already been rising slowly for months, jumped sharply in August when the airline's second-quarter results beat analyst estimates.

For the busier third quarter ended Sept. 30, analysts are estimating that Air Canada had about $3.4 billion of revenue, up about three per cent from $3.3 billion a year earlier.

Air Canada is also expected to have $1.03 per share of adjusted earnings, up about 25 per cent from 82 cents in the third quarter of 2012, according to estimates compiled by Thomson Reuters.

Air Canada's class B shares last traded above $5.80 on Aug. 15, 2008, when they opened at $5.88 and closed at $5.83.

Even with the recent rally, Air Canada's shares are worth far less than when the company returned to the public market in November 2006 at $21.

Air Canada is scheduled to release its third-quarter results on Nov. 8, before markets open.