User blog comment:Miskos3/Fairy Tail Chapter 367: Jellal vs. Oracion Seis, Review/@comment-4449950-20140121084703/@comment-4829046-20140121152347

Long story short though, Natsu pretty much stated that its all in the mind. In his mind, he convinced himself that Happy and the Legion were not transport. Similar thing here. He considers Tartaros HQ as a building on land. Then again, I don't really think these details are that important, to me it just feels like Mashima forgot about it. =P