LE BOURGET, France - Worries about passenger traffic, credit markets, the global economy and the unexplained crash of Air France Flight 447 have marred the atmosphere at the world's first and largest air show.

While defiant Boeing Co. executives said the overall prospects were robust, the Chicago-based aviation giant reported no new orders at the Paris Air Show on Monday. Airbus announced just one, from Qatar Airways, for 24 jets from the A320 family worth US$1.9 billion.

At the opening day of the industry's last major show, in Farnborough, England, a year ago, airlines from oil-rich Middle Eastern countries booked orders for about 150 planes worth more than $25 billion.

Gulf-based carriers were among the few pulling out their chequebooks this year.

Qatar Airways' head, Akbar al-Baker, announced firm orders for 20 single-aisle A320s and confirmed a commitment for four A321 jets announced last year at the Farnborough Air Show.

He said the deal announced Monday is worth $1.9 billion, which is about the same as the list price. Airlines, however, usually negotiate steep discounts to catalogue prices, particularly during grim economic times.

Meanwhile, Rolls-Royce PLC signed a $1.5 billion order with Gulf Air to supply engines for the Bahrain-based airline's new Airbus A330 long-haul aircraft. The British aircraft engine manufacturer will supply Trent 700EP engines to power 20 Airbus A330 aircraft, with deliveries beginning in 2012.

Russian planemaker Sukhoi, peddling its SuperJet 100 at the air show, netted promised orders from Hungary's Malev for 30 jets worth up to $1 billion. But it was a commercial sleight of hand, since Malev was bought by Russian state-owned bank Vnesheconombank in a high-profile deal earlier this year.

The SuperJet 100, seen as key to Russia's attempts to revitalize its civilian aircraft industry, is designed to fly both regional and medium-haul routes. SuperJet International is a joint venture between Italy's Alenia Aeronautica and Russia's Sukhoi Civil Aircraft.

Canada's Bombardier announced it had won, confirmed or converted a total of 35 firm orders for its CRJ1000 NextGen jets by Spanish regional carrier Air Nostrum, in deals worth a total of $1.75 billion.

Boeing warned last week not to expect a flurry of orders. Its defence business is hoping to make up for lagging commercial sales -- and weakening U.S. military sales -- through rising international exports.

Boeing Integrated Defence Systems (IDS) announced on Monday the launch of a new Unmanned Airborne Systems division, which will group all the company's drone projects to better compete for military contracts.

The formation of the new division reflects the growing interest by various air forces in unmanned aerial vehicles for everything from high-altitude surveillance and coastal patrols to tracking natural disasters.

Boeing's commercial aircraft chief sought Monday to strike a positive tone.

"At this point it appears to us that the economic conditions have bottomed," Scott Carson, president and chief executive of Boeing's commercial aircraft division, said Monday. "If they have bottomed and a recovery comes next year, I think we have a shot at getting through."

Boeing recently cut its outlook for the commercial aircraft market for the first time in at least a decade, which Carson said was mainly driven by the drop in freight traffic due to the global recession.

Carson said long-term prospects for the industry "are as robust as they have ever been."

However, he disappointed hopeful attendees who thought Boeing might spring a surprise first flight of the delayed 787 jetliner during the show. "The airplane will fly when it is completely ready," he said.

So far this year, Boeing -- which is cutting 10,000 jobs -- has taken orders for 73 planes, but with cancellations of 66, the net order intake is only 7 jets.

Airbus' order tally advanced to 56 on Monday after the Qatar Airways order. After cancellations, net orders to date total 35.

Both planemakers are cushioned by order backlogs of around 3,500 planes.

Already reeling from the global recession, the industry gathering near where Air France Flight 447 should have landed only two weeks ago has been shaken by the still-unexplained crash. Investigators have only two more weeks to find the flight data and cockpit voice recorders from the Airbus A330 jet before the signals emitted by small beacons on the so-called black boxes start to fade. Without them, the cause of the May 31 accident may never be fully known.

"We are supporting the investigation as much as we can and we very much hope that the recorders will be found soon, so that we find out what really happened," Airbus CEO Tom Enders said Monday.

He defended the A330's record as "very, very impressive." He said they have "more than 16 million flight hours, more than 3 million flights and this is so far one of the safest commercial aircraft built."

The Paris Air Show is marking its 100th anniversary. It opened to industry on Monday, and then to the public Friday to Sunday.