A koala became an unlikely plane passenger this week on board an Eurowings flight from Dusseldorf to Edinburgh

"The koala needed the entire row to himself as the creatures are a sensitive breed and can be highly strung."
Not to mention an additional seat for his emotional support person.

At least (the photograph shows) he was crated. Koalas can bite. Having been bitten by (other people's) pet monkeys (not on vehicles but once in my own home by a visitor's "pet") and fiercely growled at by a "companion" dog on a train I believe all animals (including pets) should be crated on public transport, especially aircraft.

"from Duisburg Zoo in Dusseldorf, Germany"

Or, more accurately, Duisburg Zoo in Duisburg, Germany. It's a different city.