As previously said, make sure it’s as private as it can be. FB has come along way in that regard. Some people you can’t see anything except one profile picture and nothing else unless your friends with them.
As far as airlines looking. I don’t know this for certain and it’s just my opinion, but I think the whole creeping on FB is way more to do with the 9-5 Corp America jobs. Literally every pilot candidate has some stupid stuff on their FB from time to time.
I honestly don’t think airlines pay much attention to this. Now executive or management positions in the corporate world? I think so.