High rankers on the level of Evankhell can completely obliterate cities

So to explain why they move around with so many people/as such a large group. Truth be told the military division's warships are only called airships in one sense of the word, they're more akin to cities.

And to move such a gigantic structure requires a lot of manpower. The more people you command, the stronger/the more power you wield, with the downside that you're responsible for providing for a lot of people

So basically, if you're a high ranker on the level of Evankhell, completely obliterating a city is no big deal

Of course the bigger the force is, the stronger the ranker ruling that group of people is, so this is why (those high rankers) can't wreck havoc just like that.

Vol.2 Ch.324: 44F - The Last Station: Evankhell (2)