Others have noted that traveling can produce quite a bit of waste. But I was surprised by two contrasts between all of the Spanish restaurants I visited and their American counterparts.
On the beneficial side, the only outright trash produced at my table was paper napkins and a few toothpicks over the course of the week. Even the cheapest, most touristy restaurants provided metal utensils, real plates and glass cups. My hostel also provided reusable dishes and utensils at breakfast, even if they were plastic. I did go to a few restaurants that provided cloth napkins as well.
One of the more unfortunate differences was the anti-tap water sentiment. I carried my own water bottle that I filled at the tap whenever I could, but admittedly the taste of the city water wasn't fabulous (just for comparison, I haven't found city water in the US that bothers me taste-wise). The bad taste is the reason given for why all restaurants only serve bottled water. Nicer places served water from glass bottles, but others gave out plastic bottles. The city seemed pretty recycling conscious, with bins everywhere in the streets, so I can only hope the bottles were eventually recycled.
I also noticed a difference in the amount of plastic included in my airplane meals. Two trans-atlantic flights meant a pair of in-flight meals, one on an American-based carrier and one on a European carrier. There was less plastic, and less trash in general, involved in the lunch I ate on the Air France flight than the dinner on the Delta flight. However, it's entirely possible that this difference was based on my class - I got bumped to business class for the AF flight home, so I couldn't actually compare economy meals.