Ashelia follows Balthier into the vehicle, staying silent except for a quite, "Hmph," choosing to listen to her companions. Her quietness has less to do with learning all she can about everyone by listening to them. It's more to do with the fact that she's been thrust into this team dynamic and she still isn't quite sure who Amalia is yet. Is she aloof? That sort complimented Balthier's personality well, but her life didn't revolve around him. Her words on the Bahamut came back to her. I am simply myself. No more and no less. And I want only to be free.

What is she even doing?

So she just rests one hand on the pommel of her sword, leaning on an arm rest and crossing her legs languidly. If nothing else, she can maybe inspire some confidence in her companions by acting in such a manner.