Are flights more dangerous than bus rides?

Question

It is usually known, that during long-haul flights some measurements must be taken to avoid veins clots. Eg.: stand up and walk once a while or take a antithrombotic shot before flight.

Yet I never heard of similar advice before long-haul bus rides, and they can take even longer (eg. bus from Buenos Aires to Lima takes 3 days).

Are flights more dangerous than bus rides, or are they equally risky?

Answer 1

There are some claims (common but contested) that the lower air pressure (and humidity) in a plane's cabin increases the risk of thrombosis.

Another factor is that buses usually have toilet breaks every couple of hours, which gives everyone an opportunity to stretch their legs - and people are more likely to make use of these opportunities than to do it regularly in a plane because there is more room and they're reminded and encouraged by the bus stopping and lots of others getting off.