If Rainbow hadn't been flying, her hooves would've dragged the entire way back to where the Wonderbolts were located at the edge of Canterlot park, which itself was at the edge of Canterlot. Bringing up Rarity's boutique had really bothered her, because now she was really thinking about it, and she did miss them a lot. A messed up part of her almost wished she'd been captured as well so she could be with them.