This statement has me a bit puzzled. Does it mean the process of airline flying is terrible or the the act of flying is terrible.
It could be someone talking about actions that are bad for climate change.
As a native speaker, my first impression was that the person is afraid of flying.
Jag håller med! Jag är rädd för flygplan.
Translation: I agree! I am scared of airplanes.
"I think that it is terrifying to fly." is not accepted.
Therefore, I have to ask: what is the context of this sentence?
My first thought was that the person is afraid of flying, like you said. However, I'm not entirely sure "terrifying" is a close enough translation of "hemskt" to be accepted.
still the safer way to travel