Organizers of the Singapore Airshow said $12.3 billion in airplane deals were signed at the event this week, a sharp drop from the last show in 2014.Leck Chet Lam, managing director of Experia Events, said Friday that this year's figure was comprised of 10 deals, with another 40 made at undisclosed values. There were 24 undisclosed deals in 2014. The 2014 show generated $32 billion of sales.Organizers released this year's total which covers commercial, private and defense deals after the three-day trade period ended Friday.Modest airplane orders for Boeing and Airbus announced earlier in the week hinted at a lull in demand, as overflowing order books at the manufacturers and a fall in oil prices spurred airlines to keep their older less fuel-efficient planes for longer."Many Asian airlines placed large orders between 2011 and 2014, and now have a long pipeline of aircraft deliveries to absorb over the next four years," said Rajiv Biswas, Asia-Pacific Chief Economist at IHS Global Insight.