I understand that air lines have to use at least 80% of their traffic slots, or they will have them taken away from them. As nobody wants to fly because of the virus, it means that the planes are flying empty. That can't be good for the environment, or for the profits of the company. They should be able to reduce their obligations, or maybe they should use the flights to carry freight.
Mentour pilot talks about ghost flights in this video -
https://www.youtube.com/watch?v=EVzMXQ8Qx_syep
airline companies buy slots a year or more in advance and have the guarantee of that slot. this is why when you book a flight months in advance you already can see what time the flight departs. as flights are not just randomly assigned on the day.
its why flights to a certain destination leave at the exact time each day. as thats the locked in schedule thats been booked months prior
however these flights are not just ghost fiights just to keep the slots costing them 100% loss in both directions. but also although for instance the UK stops wanting to let people go to china. the UK still wants brits in china to come home. and obviously there needs to be a plane to bring them back, thus there needs to be a plane(empty) going there in the first place to be in china to then come back.
most of the time they do make money by getting funding from governments by classing it as a 'evacuation' rather than just being a normal service of taking people back using their normal return flight ticket.
they also make money from freighting mail/parcels
so the losses are not as huge as you may think.. yes still losses. but not to the extent of thinking they make absolutely no income going in both directions(basically not 100% loss both ways)
also part of declaring corona as a pandemic is to also give ammo that this is not a normal event and such allows the airlines to request that in special events of pandemics or civil war they can keep their slot allocation even without flying which is what they are trying to do.. and extend it so that the special privilege can be instantly implemented for future events to save having to waste weeks/months doing it again next time
all in all
plane fly with just parcels and mail and make profit. so having no passengers and no passenger luggage means less fuel needed thus bringing a flights economic balance to that of just mail/freight costs which again evens out. and then getting a subsidy from government for classing the return flight as a 'evacuation' helps them.
so its not some large industry killer
the stupid part comes into it where for instance flybe which never even travels to china thus not affected by any of those lockdowns nor would profit from government 'evacuations' subsidies. seen alot of people cancel their flights.
this is more to do with flybe working on a shoestring budget where they were only paying hand to mouth and could only cope with a month of possible issues.
yep a few people got scared to travel even to europe and flybe didnt have reserves to weather out just a couple months. so they closed. not due to corona itself but due to it own internal mis-management of not thinking long term