With the speech bubble in the way this is closest to having the Archons on the ground I could find http://www.giantitp.com/comics/erf0056.html and from where Charlie first contacted them, but at that distance anything can be made to look on the ground.

I believe it is a unit classification that limits it not whether or not it can be on or off the ground the same as Bogroll has 0 move and is limited to GK due to his Garrison classification, there must or is a mechanic that is not visible within a "plot/story" that would explain every units abilities. Using http://www.giantitp.com/comics/erf0044.html as the basis, due to Parson saying there is "probably a million more I don't know about yet"

Let's sit back and read the story first then put in the pieces of the puzzle as we get them. I find myself going back and reading several strips in the past and the klogs to get a better understanding of the mechanics. I am a gamer first / story interested second in general terms, however Erfworld has actually changed my order thinking to make the mechanic(s) we see and read fit into the "plot/story" principle.