Didn't think to ask, if the Dinosaucer mothership has any invisibility. It was used only in 1 part of an episode. It seems either the Tyrannos don't have it or don't care to use it.
Though when the ships fly around there is no response from any military except for 1 episode I think so it could be either an oversight by the writers & no one caught that or they may all have invisibility, but it may only work vs other lower tech societies, & be useless for against each other since they can, maybe, see each other. Not sure how you want to handle that one.
Either that or the Dinosorcerer or Sorceress had a talk with the UN of the earth and whatever they said is why most of the militaries of the world don't seem to want to get involved.