Her cat ears certainly picked that up, and she pushes her whiskers forward, amused. Twitching her tail pensively, she ventures, "We could go a lot faster if I carried you in my mouth, you know. Like a kitten." Little as she expects him to like the idea, it's sort of growing on her: she wouldn't have to worry about him falling, fewer two-leggers would look twice at them, and they'd get to the TARDIS faster. Not as fast as flying, of course, but if he balks at the idea of her picking him up now, there's no way he'd consent to her doing it in bird shape.