News of new aircraft, orders and technology rained from the skies last week at the Paris Air Show, where a bumper crowd of producers and customers dodged a real downpour with mingled curses and exhilaration. The biennial event at Le Bourget airfield is the aviation world’s biggest jamboree, and every manufacturer and supplier struts its stuff in the hope of attracting more business.

Things are looking bright for the civilian side of aerospace these days, though not for defense, with budget cuts in developed countries. As emerging economies grow, enthusiasm for air travel is growing even faster. Technological advances have made aircraft cheaper and cleaner to run, so airlines everywhere are keen to replace older planes.

According to Boeing’s annual forecast, published this month, more than 35,000 new aircraft — worth perhaps $4.8 trillion — will be needed over the next 20 years. Almost 25,000 of them will be ­single-aisle planes, and almost 13,000 of them will be used in Asia. This is a market that Western manufacturers — two in particular — now dominate.

Airbus got off to an early public-relations lead with the maiden flight of its new A350 on June 14. The 314-seater boasts a 25 percent lower operating cost than its predecessors, thanks to lightweight composites and a new Rolls-Royce engine. By midweek Airbus had added 59 to its original 613 orders for the aircraft, and more for its older models. Even its little-loved double-decker superjumbo, the A380, got a look-in, with its first order since last October.

Chicago-based Boeing insisted it had expected to be outsold in Paris by the home team (Airbus is owned by the French-German-Spanish EADS). But Boeing still managed a creditable haul of its own. And it took the next-generation fire to the enemy, launching a stretch version of its midsize 787 Dreamliner, briefly grounded this year with battery problems, to compete with the slightly larger A350, and revealing over 100 new orders for it.

Boeing also upped the stakes against the upgraded “neo” version of Airbus’s single-aisle A320, due to go into service in the second half of 2015, by promising to bring forward the first deliveries of its competing 737 MAX from the end of 2017 to the third quarter.

But for once it was not just “the usual ping-pong between Boeing and Airbus,” as French television put it. Other firms, including ones from developing countries, have long been eyeing the mainstream single-aisle market, where growth is strongest. They are closing in.

Closest of all is Bombardier of Canada. Pierre Beaudoin, its boss, promises that its new CSeries, aimed at the 100- to 150-seat market, will make its maiden flight this month, give or take a week, and that deliveries will start in 2014.

Bombardier has 177 firm orders for the plane so far. It will be the first to use Pratt & Whitney’s geared turbofan engine, the closest thing to a big idea enginemakers have had for a while. Replacing the usual shaft between fan and turbine with a gear allowing each to revolve at its optimal speed should cut fuel use, emissions and noise significantly.

Embraer, the Brazilian firm that is Bombardier’s biggest rival in the market for smaller regional jets, confirmed at the show that it would revamp its E-Jet, designed for the 70- to 130-seat market, and said it already had 300 orders and options for the new version. It does not intend — yet — to compete against Airbus and Boeing, but it will overlap with the smaller version of Bombardier’s CSeries. And it will also use Pratt & Whitney’s new engine.

Russia, too, had aspirations on display in Paris: Irkut, owned by United Aircraft Corp. (UAC), displayed a mock-up of its planned 130- to 150-seater MC-21, which will again use the geared turbofan engine (and eventually a Russian one). Irkut expects to start building the aircraft this year and to fly it in 2015. Another firm from the UAC stable, Sukhoi, has until now been selling its smaller Superjet mainly in Russia and other former Eastern Bloc countries. Thanks to a joint venture with Alenia Aermacchi of Italy, the first Sukhoi Superjet destined for a Western airline was handed over in Paris, to Interjet of Mexico.

Among the missing at the air show was China’s candidate to take on Boeing and Airbus — the COMAC C919. The 150-plus seater was scheduled for a maiden flight in 2014, but development has been knocked off course.

It is the Chinese that both Boeing and Airbus claim to rate as their only serious mainstream competitor, despite Bombardier’s lead.