If you can imagine the Paris Air Show as a stock market then what it has enjoyed this week is a nothing less than a rally–and a very welcome one at that. The world’s aerospace industry arrived here at Le Bourget on Monday morning in a torrential downpour of rain that seemed to symbolize its torrid fortunes over the past year. It will go home over the weekend, slightly sun burned and basking in the warmth of an unexpectedly strong flurry of sales activity.

Until the worldwide financial crisis pulled the rug from beneath its feet last year, the industry had enjoyed a phenomenal wave of good fortune on the international airshow circuit over the past five or six years, with order tallies being counted in the hundreds of billions of dollars. Most observers predicted slim pickings here this week, but as the final trade day of Paris 2009 dawned this morning the bottom line looks to be better than expected.

As of last night, the tally for new aircraft and engine orders announced here over the first three days of the show stood at just under $29 billion. On top of this there have been countless orders for related business covering services such as maintenance, training and customer support.

But it would be irresponsible and groundless to suggest that the aerospace sector has turned a corner this week. The grave uncertainties over economic fundamentals are as real today as they were on Sunday night. For all the wishful thinking, none of the experts assembled here in Paris can offer any definitive conclusions as to whether the long-anticipated bottom of downcycle has yet been reached.

Nonetheless, the cash committed by airline customers this week–largely those from Asia and the Middle East–will eventually trickle down the aerospace food chain and replenish dwindling coffers and, hopefully, bolster confidence–confidence that could drive yet more orders.

So what impact has the recession had on the Paris Air Show in its rightfully proud centenary year? Organizers are bullishly expecting the final audited figures to show trade visitors numbers to end up pretty close to the record figure of 153,920 who came to the 2007 show. That may or may not prove to be the case, but it is no secret that many exhibiting companies have opted bring fewer employees to the show as part of their cost-cutting measures.

As the industry moves on to the next wave of airshows–Hong Kong’s Asian Aerospace in September,  Dubai in November, Bahrain in January, Singapore in February and Farnborough next July–these events should give us a more coherent indicator of the trajectory and velocity that the industry’s recovery might take.