As epidemiological countermeasures, why are flights cancelled and surface transport is not?

Question

An early measure to avoid the spread of COVID-19 has been the cancellations of flights from infected zones, e.g.: https://www.reuters.com/article/health-coronavirus-spain-flights/corrected-spain-cancels-flights-from-italy-for-two-weeks-in-a-bid-to-stop-coronavirus-idUSE8N29W006

(I wonder about the effectiveness, specificity, and sensibility of such measures, for instance, if I am a tourist that has been barely in contact with locals, it should be better to go back home, in isolation if necessary. But that is a different question)

However, surface connection has not been cancelled, and I could go back from Italy to Spain driving or by train. Also ships continue travelling, although maybe moving from Europe to US would not be that practical...

Is there a purely epidemiological reason why air transport is inherently more prone to contagions, or otherwise more dangerous? Or is it just that it is easier for a government to close airports than roads?

Answer 1

Flights are much faster than cars/trains/boats. In turn, that means COVID spreads slower if cars/trains/boats are the only viable means of transport. It also means that COVID spreads in a connected way: if there was no air travel for example, you would not expect to see COVID in Europe before it hits Western Asia. With it, Europe can be affected first.

Compare e.g. what happened with the Black Death. During that time when the fastest means of travel was by horse, it took several years for the disease to spread around Europe, and it never actually reached China. These days, it only took a few weeks for the disease to get from China to Europe, and then around the world.

Answer 2

Air transport has been cancelled in different countries differently. In the US, they cancelled all air transport from EU. In several EU countries only air transport from China, Iran and Italy (countries with moth infections and deaths) has been cancelled. In Europe, initially most infections were spread from Italy.

Countries that border to Italy have severely restricted land transport from Italy. Austria has completely closed the border. Some countries do not accept trucks that come from Italy.