The first time I saw a Kindle was on an aeroplane some years ago, flying out of Heathrow for, I think, Schiphol.
It was my brother's, a man who travels extensively on business. Which means a lot of air time, which means a lot of books to kill time. Which means a Kindle (or of course any equivalent--it just happened to be the sort he owned). He has a wide assortment of books, including short story collections, constantly changing, on his device, ideal for short or long-haul flight.
As for taking books on holiday--are they kidding me? I don't takes books on holiday; I can sit and read at home. Holidays are where I go do something different, whether it's fell-walking in UK, exploring New York on foot, goggling at puffins in the Hebrides, or sitting at a sidewalk cafe in Italy enjoying good food, good conversation, good wine and good company. I used to pick up a book at the airport bookstore before a flight (it's a long haul from Australia to UK), but strictly for inflight reading.
I can't really grasp the idea that what I should do on a holiday is sit in a chair and read a book.
I'm right there with fjtorres: what the survey says is that 21 percent would prefer to take an e-reader. That's a surprisingly large number. Way up from the first time I saw a Kindle in action some years ago, when my brother's was probably the only one on the 737.