To retain this cash, Air France-KLM and Lufthansa, for instance, have offered generous rebooking options and issued rebooking vouchers. "These measures should not be underestimated: Lufthansa had EUR 4.0bn of liabilities under unused flight documents at the end of 2019 versus total gross financial debt reported of EUR 6.8bn of which EUR 6.1bn were long-term financial obligations," says Stäblein. The second is scaling back of plans to modernise or expand fleets of passenger aircraft. "Airbus and Boeing were set to deliver around 430 aircraft in Europe this year – assuming no extended grounding of the US plane maker's B737MAX aircraft over safety concerns but it now looks unlikely many of those deliveries will be made," says Chammem. Lufthansa, for example, plans to "drastically" reduce its EUR 3.0bn capital-spending budget for 2020.