MONTREAL (CP) -- Bombardier may have to revise its business jet forecasts after an industry association said its deliveries continued to fall in the third quarter.

The Montreal-based manufacturer delivered 36 business jets during the third quarter, down nearly 37 percent from the 57 aircraft shipped a year ago, according to the General Aviation Manufacturers Association.

Corresponding revenues fell to US$1.02 billion from $1.42 billion.

Third-quarter shipments marked a deterioration from year-over-year declines in the first half of the year. Bombardier had delivered 50 planes in the second quarter, down 25.4 percent from the year-ago period. It sent 54 planes in the first quarter, a drop of 19.4 percent.

During the first three quarters of 2009, the industry delivered 615 business jets, down 37.7 percent from 988 in 2008.

Bombardier spokeswoman Danielle Boudreau said its lower shipments were expected because of weak economic conditions this year and comparisons to a strong period in 2008.

"Last year was a record year so definitely we were expecting a decline this year," she said in an interview.

Bombardier said it expects business jet deliveries will decrease by 25 percent this year.

It is in the process of laying off 4,360 employees as it reduces production of business and commercial aircraft. Regional jets, which are sold to airlines, are estimated to account for 1,200 of the layoffs.

The manufacturer has yet to forecast deliveries in 2010, but some industry observers have suggested it may have to further reduce production rates.

Boudreau said a deliveries forecast for next year may not be available when the company reports its quarterly results Dec. 3.

She noted that among all manufacturers, Bombardier has come out on top again in terms of revenues and units for the eight business jet segments in which it competes. It doesn't make ultra-light planes.

Benoit Poirier of Desjardins Securities said he expects positive news for business jet manufacturers.

"We believe the worst is over for the business jet market, although a recovery could be gradual," he wrote in a recent report.

Poirier expects Bombardier's business jet deliveries will decline 30 percent this year and 15 percent in 2010.

According to the manufacturers' association, Bombardier's smaller business jets sustained the biggest hit during the quarter. It delivered six Learjet 40 and 45 aircraft, down from 15 a year ago, and eight in the second, and 14 in the first quarter.

Four Challenger 605 were shipped, compared to 11 a year ago. Nine were delivered in the second and 15 in the first quarter.

Deliveries of larger business jets were more stable. It shipped four Learjet 60s, eight Challenger 300s, 11 Global Express and three Challenger 850/870/890s.

Total airplane deliveries have fallen 46.8 percent, from 2,982 units in 2008 to 1,587 units so far this year. Total industry billings are down 23.5 percent, to $13.8 billion.

North America accounts for about 76 percent of all airplane shipments.

Association president Pete Bunce said airplane shipments and billings were affected by impact of the weak economy.

"However, another contributing factor that has led to the disappointing year-to-date numbers is the unwarranted negative attacks on business aviation," he said in a news release.

On the Toronto Stock Exchange, Bombardier shares closed at C$4.59, up eight cents or 1.77 percent.