He looks up at her, confused. "The what?" The reference is utterly lost on him. He doesn't plan to stop, except for food, gas and restroom at any time. He wants to put as much distance between him and DC as possible.

Bucky isn't sure which of the governmental agencies is after him - SHIELD, HYDRA, CIA, FBI, UN... pick an aphabet - but it can't be good. He has to be prepared to leave her behind, too. He knows she won't leave him, but if he has to lead them away from her? He'll do it.