I have never flown en femme but I have been working to push my boundaries recently.
I've ridden the train several times and earlier this week I even took the VIP tour of Cowboy's Stadium en femme. That took a lot of nerve but it was fun and I have no regrets.
I know if you don't do this you will feel the regret and spend a lot of time wishing you had done it.
The key is self confidence. Let that self confidence show and everything will be fine.