Aviation is the most global of global industries. It employs millions of people, underpins the livelihoods of tens of millions more, and acts as part of the central nervous system of international business and leisure.
Yet now vast parts of the network have been shut down as a result of the coronavirus pandemic. The number of daily flights has fallen by 80% since the start of the year, and in some regions nearly all passenger traffic has been suspended.
The industry is in survival mode, with airlines, airports and ground-handling firms all desperate to conserve their cash reserves, while their normal revenue streams have dried up.
Widespread job losses are now expected, with British Airways' parent company IAG announcing on Tuesday that it is set to cut up to 12,000 positions from the airline's 42,000-strong workforce. IAG said it did not expect BA to see passenger demand return to 2019 levels for "several years".
Elsewhere, Easyjet has laid off its 4,000 UK-based cabin crew for two months, Qantas has put 20,000 staff on leave, and 700 pilots at American Airlines have agreed to take early retirement.
Even so, attention is now gradually turning to the future, and how airlines around the world can hope to slowly return to something approaching normality.