The correct answer is 5. Seat 3 IS next to arguably the nicest passenger already on the plane, but you know Trump is putting his seat back as far as he can, and Jones yelling near your ear the whole flight? No.
I've seen Vance's donut shop banter. He's the least likely to blather on for the whole flight, and I'm not a couch, so there's some safety there.
You get to seat 5. "How long have you been on the plane?" he asks.
Tex: "Five minutes."
JD: "Ok." <Long Pause> "You also going to San Diego?"
Tex: "Yeah. We're on the same plane."
JD: "Ok."
An uncomfortable smile-ish sort of thing from him: "I'm running for Vice President of the United States," a confused and pitying look from me: "Ok," then it's just turn and look out the window for the rest of the flight, with an occasional "You're 'accidentally' touching my leg again, JD" rebuke, and a weird "Ok," from him. Then hopefully we're almost in San Diego by then.