The water weight I am referring to is what I collect internally, and which is aggravated by how much sodium I consume. At home, I've been aiming for 1000-2000 mg sodium per day. And let me just say, yes, I _do_ read the labels that carefully. I buy sodium free baking powder (Featherweight), peanut butter, bread (or make it myself). I buy no salt added soup (Health Valley Vegetable), mustard (WestBrae Stone Ground NSA) and even, most recently, deli turkey (Dietz and Watson NSA -- dry, and tastes just like turkey you might cook yourself if you don't brine it). So I can hit that 1000-2000 mg target consistently. And it works insanely well. After years of a 3 pound daily variation in weight (tell me _that's_ not water), I had it whittled down to under 1 pound while pregnant.
Travel, however, is much trickier, especially since I did not plan this trip around cooking meals but rather around socializing with friends in their homes or at restaurants. Sodium in these environments is elevated and really hard to do anything about. By the end of the trip, I was up at least 5, maybe 6 pounds. 3 pounds disappeared between arrival night and the next morning. Another 2 last night. And my ankles are no longer puffy.
Sure, some of it is traveling on airplanes across country. Sitting in one place all day just isn't good for me, and apparently not for a lot of other people either. But I doubt that was all of it, because my ankles were kinda puffy before I got on the plane for the return trip.
It's a little bit of a pain adjusting to the reduced sodium, and I wasn't doing this because of current high blood pressure problems (altho the elevated blood pressure at the end of my first pregnancy was a cause for concern and planning this time around, of course). But I've been quite surprised at how _well_ cutting sodium works, and would recommend the process to anyone else who suspects they're sodium-sensitive.