We have tried audiobooks with the children when they were younger and it did not work, especially in the car, on the highway. It was too noisy for them to actually understand what was being read.
This time to our Maine trip, we tried it again and I was so surprised by how much they (and us) like them!
We borrowed ours from the library (electronically, so we didn't even have to step out of our house to do so) so they are free! There are also some books that you can get for free online.
This time this book was our favorite. A.A. Milne wrote a delightful book about THE bear. The performers were so talented and we enjoyed every bit of the British accent. =) We actually finished the whole book (and repeated some chapters).
Our trip took us 12 hours to and fro and also some many hours in between when we go on day trips.
We finished Winnie-the-Pooh, The house at Pooh Corner, Cricket at Times Square, parts of Fancy Nancy and almost the whole of Vile Village (A Series of Unfortunate Events).
The older three were thoroughly "entertained" throughout the trip and "read" many books. The youngest was fussy because of illness.