Flying pregnant tips!

Taylor • Married. Brooks born 8/2015. Baby Eleanora Quinn due May 2018. 💞
My husband and I will be traveling from where we live in Pittsburgh, PA all the way to Seattle, WA, in a little less than 5 weeks to visit my FIL. I'll be about 24 weeks when we arrive and 26 when we depart. My doctor said they're going to give me my records to take with me just in case the airport questions me or anything like that. We have a layover so the trip will be somewhat broken in half. 
Do you ladies have any suggestions for air travel, aside from the obvious keeping extra hydrated and getting up and walking on the plane to help with circulation? Hopefully this trip doesn't end up being too exhausting, and the 3 hour time change won't mess with me too much!! Any tips or suggestions are appreciated. I've flown a million times, just not pregnant!! Thanks!!