Related: We travel internationally quite a bit and have long since given up carrying books. They are heavy and bulky. Instead, we both read on our tablets - Google Nexus 7s. They also double as email readers and for internet browsing when we have wifi. Amazon also has a line of e-reader tablets beginning well under $100.
Our local library has a pretty broad collections of e-books that can be borrowed for free. There are also many, many books in the public domain. And then there are purchased e-books. We can easily go on a trip with 5-10 books at a cost of the few ounces that the tablets weigh. Then we don't have to be so discriminating in selecting the exact right book. We just carry three or four and maybe completely read one or two of them.
These days, too, most long-haul airplane seats seem to have power outlets so battery life is not an issue.