If you are stuck in a middle seat and want to use muscular pumping to move fluids out of the lower legs, be a musician. Classical musicians toe tap leaving the heel on the floor, while jazz musicians raise and lower the heel keeping the toes on the floor, or so it has been said. Doing both kinds of tapping pump the leg muscles and squeeze blood upwards. A hundred taps of each type for each leg will move a bunch of fluid.

Perhaps someone has already said this and I missed it, but not only do they make pressure stockings with different levels of pressure (or tightness, if you will), but they also make the kind that go all the way up to the upper thigh. If socks don;t suffice, you might try these. (Note also that "tight socks" are not at all the same as proper pressure stockings.)

Indeed, NewbE, therapeutic hose are made to provide graduated pressure - more at the foot/ankle and decreasing up the leg in order to promote venous return. To just wear tight socks woulds actually be a hazard

Thanks everyone very helpful
I see you ref the Mayo clinic, as a Brit I have no idea who they are, do they do original research in this area or are they a bunch of GPs. Any advice?

The Mayo Clinic is one of the preeminent medical research centers in the US. It's hard to name a UK equivalent, but Edinburgh University's medical school probably comes closest.

Thanks Gardy. So, vets and doctors, great.

billo, does she have trouble with blood clots. I had a similar reaction when I flew (even short distances) with swelling of my legs. If she goes on a treadmill or stairmaster and has intense pain in her legs when she walks or climbs, if she has unusual bleeding or pain in her legs when she rubs or messages them then she may have blood clots that can travel to the brain, heart, lungs.

nanbee - to clarify that symptom (intermittent claudication) indicates vascular insufficiency but not necessarily clots.

Hard to do on a plane, but if there is anyway to elevate her leg (crazy I know, but perhaps on your lap) and do hard massage from the ankle to the knee, it helps. It was recommended to a friend by her doctor. It works for me really well.

As someone else said, cut the salt and increase potassium. That was also the advice from my doctor. Start cutting the salt a couple of days before the trip. It is so easy to eat a bag of chips or something similar and that really makes it worse. It is funny that you can be dehydrated and still have your legs swell, but that happens to me, so plain water works. Coke or caffeine makes it worse.

Does she have any signs of swelling other than when she flies? The reason I ask is that I have just come thru a horrendous bout with lymphedema... started with swelling feet and proceeded up my lower legs. I live in NYC, but even so, it took me forever to get a proper diagnosis and treatment. Most doctors looked at me and send me to a rheumatologist suspecting RA. If she has no indications of a similar problem she might consult a physical therapist or doctor about getting prescription compression stockings. They are expensive but are more effective than anything sold "over the counter."

One other thought.

I don't know if you are retired, or if you have the means for this. But... What if after the first flight, you visited the USA or wherever your first 12 hour flight ends. Stay for two days. And then go on to New Zealand. The same in reverse on the way home.

I haven't read all the responses so I apologize if this was mentioned by someone else. My ankles would swell, even on 3 hour flights. I've recently cut out most processed food (read: high sodium foods) and on my last flight, my ankles did not swell at all. Granted, it was only about 3 hours, but it was a big improvement. We're flying economy JFK to LIS on April 30, and business class to Tanzania August 1, and I plan on getting compression socks for both me and DH for both flights. In any case, maybe Mrs. Bilbo should watch her sodium intake for several weeks prior to flying.

You can also order the low sodium meals on your flights.

Happy Travels!

that is interesting seamus. I had those symptoms but they were caused ultimately by blood clots. I eventually had a Pulmonary Embolism and after taking blood thinners the clot dissolved and the symptoms disappeared as well. Do you have any other suggestions. Should I talk to my GP and find out if I also have thin arteries as well?
Thanks.