PARIS -- Bombardier's largest commercial jet took to the skies of Paris on Monday to mark the opening of the world's largest annual air show.

Thousands of onlookers and customers watched as the CS300 CSeries flew in grey skies following results of flight tests that showed it's as quiet as promised.

"You will not hear it fly," new president and CEO Alain Bellemare said minutes before the flight, accompanied by chairman, Pierre Beaudoin, and his father, Laurent.

Bellemare, who has headed Bombardier since February, said the air show marks a "turning point" and a "real takeoff" for the CSeries.

"There was a lot of pressure on the program. Now we advance. We are now building a very positive momentum," he said.

Bombardier announced Sunday that the planes performed even better than expected during flight tests. Its maximum range is 12 per cent longer and the cabin can accommodate up to 15 more passengers.

Bellemare said the company can now talk to customers about the numbers, efforts that will re-energize the sales and marketing efforts. The company has 243 firm order for the CSeries, falling short of its goal of 300, and commitments for 603 orders.

At the air show, Bombardier (TSX:BBD.B) announced that Swiss airline, a division of Lufthansa, will switch 10 of its 30 firm orders to the larger CS300 aircraft with 130 to 160 seats.

Swiss CEO Harry Hohmeister said the plane's size and low operating costs complements the 110- to 130-seat CS100 and the rest of its European fleet.

The Montreal-based aerospace manufacturer also announced Monday that WestJet Encore has signed firm orders for six more Q400 turboprops, eventually raising the Calgary-based regional carrier's fleet to 36 aircraft.

The five planes, plus another one booked in March, are conversions of previously announced options valued at about US$200 million, based on list prices.

Encore is adding planes as WestJet's Airlines Ltd. (TSX:WJA) expands the regional service to eastern Canada. The five planes will be delivered in 2016 and 2017.

Launched two years ago, Encore now has 114 daily departures to 24 cities in seven provinces.

The orders come as unions are reportedly trying to separately organize WestJet flight attendants and pilots ahead of federal unionization rule changes that come into force on Tuesday that would make it harder to form a union.

WestJet pilot and flight attendant associations recently signed five-year deals.

David Tyerman of Canaccord Genuity says he doesn't expect a unionized workforce would significantly increase the airline's costs but could reduce operating flexibility. It could also augment the threat of labour disruption, although Ottawa has shown that it is unwilling to permit strikes at rival Air Canada.