Boeing delivered blockbuster news Tuesday as Qatar Airways had ordered 20 more 777X long-range jets, worth $8.8 billion at catalogue prices. Big orders from major clients typically win significant discounts. Both aviation titans however face huge production backlogs as they struggle to keep up with rebounding global appetite for travel. Boeing has meanwhile sought to turn a corner over safety concerns ever since a fuselage panel blew out of a 737 MAX flown by Alaska Airlines in January.