After years of big-ticket plane orders, next week’s Paris Airshow will see rather fewer multi-billion-dollar deals and rather more nervous expressions as planemakers face the daunting task of producing $1.8 trillion of jets already sold. The world’s biggest aerospace gathering will still have its fair share of announcements, including a potential 100-plane leasing order for Boeing, as well as the showmanship that goes with any public contest with European arch-rival Airbus.