What do you do with your planes when you have no passengers to fill the seats? Fill them with cargo instead.
As travel restrictions bite airlines around the world in an effort to contain the spread of coronavirus, some carriers have opted to use the empty space in their passenger cabins by filing them with cargo.
Most airlines with freighter aircraft are continuing to fly them around the world, but some airlines only have passenger aircraft in their fleets. These airlines still typically fly some cargo in the hold of their jets in addition to passenger baggage.
And while several airlines, including Qantas, have started using passenger planes to make cargo-only flights, a handful have gone a step further and started filling their passenger cabins with freight.
Ireland's national carrier, Aer Lingus, on Sunday tweeted an image of an Airbus A330 on its return from China, with its economy class seats stuffed with cargo bags. Similarly,Germany's biggest airline Lufthansa and its subsidiary Austrian Airlines have also been using passenger cabins for freight.
The International Air Transport Association (IATA) issued guidance for airlines on how to safely transport cargo in passenger cabins last week. The IATA said no dangerous goods or live animals should be transported in the cabins and that normal weight limits for seats and stowage should be applied.
The IATA said demand for cargo slumped 9.1 per cent (seasonally adjusted) in February compared with January. As travel restrictions were implemented around the world, airlines faced delays on getting permission to fly shipments, which created bottlenecks, according to the IATA. In addition, the huge drop in passenger flights also reduced available cargo capacity.
As a result, global supply chains have struggled to deliver vital supplies and equipment needed to fight the COVID-19 virus.
"It is critical for governments to remove any blockers as the industry does all it can to keep the global air cargo network functioning in the crisis and ready for the recovery," said Alexandre de Juniac, IATA's director general and CEO.
On Saturday, five Cathay Pacfic Boeing 777 passenger planes arrived in Brisbane with only cargo on board. The five jets were carrying more than 700 cubic metres of medical supplies, including protective gear for healthcare workers. The supplies are expected to be distributed nationally in the coming days.
In the US, American Airlines made its first cargo-only flight in 34 years last month, flying medical supplies between the US and Europe, while United Airlines has also started using its larger passenger planes to transport medical supplies.
According to IATA figures, air cargo delivers $US6 trillion ($A9.9 trillion) worth of goods annually, including 328 billion letters and 7.4 billion postal packages.