Audio entertainment, like audio books and podcasts, is an absolute win because everyone can tune in and listen, while looking out the window at the same time. Depending on the length of the trip, you could get the whole family enthralled in some wonderful chapter books and listen through from start to finish.
Car trips are also great opportunities to talk, especially with our older kids. There's less pressure than with face-to-face conversations – you can just look out the window if things get too awkward, which our tweens and teens will likely appreciate. Keep it light, share a story or two, and throw out some questions – you never know where conversation might lead to.