iTunes in Europe

Sure, no problem, no difference. Be sure to stick to free WIFI downloads and no 3G,4G, data downloads as those would be expensive. Computers speak the same language whether in Europe or US.

There shouldn't be any major issues. You'd need to make sure that where you're staying has an internet connection (wifi or bring your ethernet cable) so you can download them. Alternatively, you could take the laptop somewhere where there's wifi, like a cafe, but public (and even hotel) wifi is a gamble when it comes to speed. At least at a hotel, you could let it download overnight. iTunes only concerns itself with the country the account's associated with. So, a U.S. account continues to work just fine even when the account holder is connecting from outside of the USA. Some services, like Netflix and TV network websites, will recognize that your computer is connecting from outside of the USA and prevent you from watching U.S. content. However, as I said before, iTunes only cares where your account is registered. Like Frank said, if you're using an iPhone or iPad that's connecting via cellular data, you want to be very, very careful and make sure that you do any downloading over wifi and not cellular data. International cellular data is typically expensive and a large download like an iTunes movie could be verrrrrry expensive.

Be aware that downloading a movie in Europe can take some time! We did this in France, and it took almost as long to download the movie as it took to watch it! We had to sit in a common area to get wi-fi, not in the comfort of our own room. In the end, it was worth it to have the movie. I'd recommend doing your downloads at home if you can before you travel if you have a high speed connection. There are usually plenty of movie choices on overseas flights, usually some early releases that you can't even get on iTunes yet! We really enjoyed watching movies on my iPad on our last trip. I'm planning to download 3-4 rental movies before our next vacation. I just bought some small rechargable speakers to compliment the sound system (got them at Costco for $40, so small, they fit in a small bag and weigh in just ounces, but BIG sound!) If you haven't ever rented a movie from iTunes, make sure you understand how it works....you have limits of time to use the rental, and once you start the movie you have to finish watching it within 24 hours. It will automatically delete from memory after 24 Hours. Also, make sure you have enough memory on your computer for the number of movies you download. watching them will free up space for more if you get close!

Now, I know some people don't like to rewatch movies, but a lot of times when we get our blu-rays, there will be a digital copy as well that you can download thru itunes and put on your tablet (pad/pod)...a lot of them have expiry dates (as I discovered when I finally got my ipad mini and went thru my movies)...our local video store (yes, we still have one here) even sells the digital copies for $5 (well, the disc or download code), or maybe you have a friend who buys a lot of movies and may not use the digital copies. That being said, other then the small screens, last year in Sept I watched more then a few movies on the plane that didn't come out on video here until a few months later, as well as listening to some music and watching some TV shows! And I picked up a really neat little speaker the folds down...about the size of an orange, at Staples for $20...iHome brand...good enough sound for the purpose since the speaker/volume on my pad is pretty cruddy.

Another option is to "rip" a DVD or Blu-ray disc from your desktop, and transfer the file to your mobile device. I use this software: http://www.pavtube.com/blu-ray-video-converter-ultimate/