Despite the fact that he didn't mean to do it, Steve still would apologize. It was part good manners to apologize, and partly to show that he understood that the last week had been difficult for them both. And when they get back, Steve will let Bucky motherhen him for a bit; it was only fair. At the same time, he'll do his best to drag Bucky into doing the same.

"Aright..." He murmured sleepily in assent, giving the thigh underneath his hand a light squeeze and left it there as he started drifting off. The suggestion that they stay at Stark Tower surprised him, considering how Bucky never entirely felt comfortable there. He fell asleep, head tilted slightly back against the headrest with a last, "Wake me up when we're almost there..."

His last words turned out to be unnecessary; he woke up at the feeling of the light bump of the quinjut touching down on the tarmac.