Safety concerns, trade wars and growing security tensions in the Gulf are dampening spirits at the world's largest plane-makers as they arrive at this week's Paris Airshow with little to celebrate despite bulging order books.

The aerospace industry's marquee event is a chance to take the pulse of the $150-billion-a-year commercial aircraft industry, which many analysts believe is entering a slowdown due to global pressures from trade tensions to flagging economies, highlighted by a profit warning from Lufthansa late on Sunday.

Humbled by the grounding of its 737 Max in the wake of two fatal crashes, U.S. plane-maker Boeing will be looking to reassure customers and suppliers about the plane's future and allay criticism of its handling of the months-long crisis.