The "oh" made him wonder if she wasn't disappointed about something, but other than it being out of sympathy he wasn't sure what she would be disappointed in. Unless she'd really wanted them to fly together. But he couldn't really help that, so he wouldn't fixate on it too much. Just show her that he was cool and fun to hang out with in other ways.
The idea of her dust making people babble intrigued him, and he grinned. "Really? What's it do, scramble brains?" he asked. That would be fun to see, definitely, and could also be useful.