If most countries have closed their borders, airlines have grounded their fleet and everyone is in lockdown, why then are there still planes in the sky?
Well, there are still limited services flying, mainly to repatriate passengers who will then be subject to quarantine periods upon their return home.
But, there are also planes that are flying with no passengers on board at all.
An internal memo published in the Dallas Business Journal, for example, revealed that 56 Southwest Airlines flights took off in a week without any passengers on board. Meanwhile, low cost carrier Ryanair has been seen flying its planes around in circles, and other airlines in Europe have wasted gallons of fuel running empty flights.
So why are they in the air at all?
There are actually several reasons why passenger-less flights have been flying. According to Southwest, it is running empty or near-empty flights as air travel is vital for the movement of personnel and cargo as well as it being potentially necessary to continue operations in order to qualify for Government aid.
The airline has also pointed out the logistical problems of restarting an airline rather than keeping one running.
At Ryanair, executives say that to make sure its planes continue to be usable to repatriate passengers and transport medical supplies, it must continue to run some of its fleet in order to meet maintenance and flying regulations.
Other flights are likely to be have been in operation to move aircraft back to base or to storage facilities. Airlines had also until very recently been continuing to run flights, even without any passengers, in order to hold onto coveted takeoff and landing slots.
Thankfully, the Federal Aviation Administration and the European Commission have, for the moment, suspended regulations which mean airlines must continue to fly a certain amount of their regular flights so that they can retain their hard-won time slots. So there should, in theory, now be fewer ghost flights in the air.