Yes this is a problem for me too, along with a very significant increase in fatigue immediately after flying. I now always ask for the wheelchair assistance at the airport. You can usually make the request in advance when you book your flight. It saves energy that you would be spending walking and makes it much easier when you land if you have spasms or leg pain.

No matter how many times I fly, I'm never sure just how my fibro is going to react. Some flights are easy pieces of cake with no pain... others I spend the whole time unable to rest because I'm so uncomfortable despite taking a sedative. The only thing I would worry about is where the spasms were. It could be a sign of something else if you're not careful. I would definitely talk to your doctor, especially if it happens again on the return flight. It could just be the fibro, but with all the things that can happen healthwise when you fly (ie blood clots, etc), it never hurts to double check with the doctor.

I get them all the time especially in my neck, chest, lower back and legs. I take lyrica (pregablin) and amytriptline to subdue them. I find stress, anxiety and depression make them trigger of more frequently and serverly.

Amazon has some great compression socks that don't look like compression socks. I wear them every time. They even have fun patterns on them that make me happy.

Also really good compression socks help.