J.C.
Hi R.,
We've traveled internationally with our daughter, at 9 months and again at 20 months. Be as prepared as possible, with items that comfort her, snacks, small toys/books and activities to help entertain her during the trip. I brought many smaller packs of wipes and put some in each bag, so I always had some within reach, as well as plenty of diapers, of course. Strongly recommend using only 'overnight' diapers for travel, as they're more absorbent than regular. Allow extra time at the airport b4 flight departs, as it will take longer for you to get through security with a toddler. As for napping, we've taken a small popup 'tent' with us, made for babies/toddlers. It folds up easily, can fit into a carry-on & is very lightweight. You may want to look into something like this (I found ours on a website, I think babies.com?) about $50 to $80 new. We used ours on the beach too and it helped keep her in the shade & away from bugs during nap time.
Another nice travel item is disposable sippy cups, you can find them with lids that lock, these were very useful and I didn't mind if one got lost. The airline we took did not allow 'lap babies' for under 2 yrs old on international flights, so we were required to purchase a seat for our child; if you haven't already checked into this with the airlines, I suggest doing so now. If you'll be traveling by car but not very much, you may want to ask a travel agent, online or with car rental in Austria & Italy if they have car seats available to rent with a vehicle. That way you won't need to take a carseat with, which you'd have to check-in on the plane if it's not used in a purchased seat. If you'll be doing a lot of walking/sightseeing, I recommend taking an umbrella stroller (small, sturdy & lightweight); you can use in the airport too & check at the gate. I don't think the airlines count a stroller checked at the gate as a 'checked' item, so you shouldn't be charged extra (I think, you'll want to ask if you do this). When you get off the plane at destination, they give you the stroller at the arrival gate; although after being cooped up in a plane for hours, your daughter will likely be ready to run around (if not sleeping!) Don't even consider taking a standard sized stroller, it will not fare well in checked luggage & it would be too cumbersome for travel.
I hope this has helped. With planning, preparation and patience, traveling with our daughter was not as scary as I thought it would be. Best of luck with your planning and have a wonderful trip!!