Hilary - just looked again and they are Lycra.
"It says Scholl Flight Socks look like ordinary socks, however, because they incorporate complression to aid your circulation you may find you cannot put them on like normal socks. "
It also says - if cared for correctly they will give you the recommended levels of compression for the equivalent of three months of continual flying.
They should be hand washed at 40 degrees C with mile detergent and dried flat.
Do not wring, dry away from direct heat - and should never be dry cleaned, bleached, ironed or tumble dried.
I dont think I would want to put them on over another pair of socks, I think they would be too tight.
Hope this helps