It does not appear to be the case as there is no exception to the rule prohibiting characters from joining flying units (p. 97) as was previously the case for chiefs on terradons.
In fact, we don't have an exception to the rule that would allow tictactoe from joining terradons. Until FAQ's, he's all alone. -Matt
That's an annoying oversight considering two of his rules appear designed to work with a unit he has joined, especially annoying considering the rule was remembered for tenenhauin
Tiktaq'to joining units is a subject of dispute. The Mask of Heavens refers to the unit which has Tiktaq'to in it. Ergo, he can join a unit.......
Actually, it says all terradons in his unit use his leadership. He is a unit, and he has a terradon in his unit (Zwoop). It is an oversight, but hasn't been corrected yet. The better question is, why would you want to take him? He's really too expensive for what you get.