I do use a moisturizer during long flights, but I also start off with a nice packable wipe (whatever face cleansing wipe I have at home - I pack in ziploc bags) I can remove makeup as needed and then my face is ready to receive the moisturizer I'll add before I try to sleep.
I also try to sleep with my hair off my face - I don't like putting it in a ponytail holder but sometimes a wide stretchy band to keep it back from my face is nice. I'll usually put it up before deplaning (I don't like using a dry shampoo on the plane but might when I get into the arrival airport if I feel like it)
Of course, I'm over 40 now, and things aren't as "dewy" as they used to be. Your needs will vary based on your age, skin type etc.