Did you know you can rent & download audio books for free if you have a library card? Zinio (RBDigital) for magazines, Overdrive (Libby) for books, and Hoopla (music/audio books/TV) are all great options. We like to listen to books when traveling by plane, train and car.
Plane headphones are typically really bad quality. You will likely want to bring your own on. This is especially important if you have the new iPhone with the different headphone connection than what airplane entertainment devices use.