I checked this book out of the library for a 5 year old I baby sit occasionally. He can't get enough of this book! While a lot of the planes are too complicated for him to build on his own, it's been a great activity we can do together. He can't read the words, but the pictures are clear enough for him to understand. There's a lot of measuring, cutting, and glueing to be done on some of the more complicated planes, but I don't think older kids would have much of a problem. I'd say 95% of the planes we've built have flown impressivly well, in fact some of the easier ones fly the best.