Interestingly (to me) I was looking at the flights over Europe on FlightRadar24 and instead of the hundreds of planes usually flying, today it is primarily the carriers - DHL, UPS and the very long range, Buenos Aries, Chicago, San Paulo etc.
The main exception is that RyanAir seem to be running as usual - Barcelona to Santiago de Compostela, Tenerife & Paris - Madrid to Prague. Iberia Airlines are also doing all their internal flights but it makes you wonder how many people are on them and why?