@Flyingfear85 I'm afraid that I don't believe you're doing your DD any favours by trying to hide the realities from her, especially if you are ALSO letting her have independence. The sad fact is that as a girl/young women, she will experience some version of sexual assualt/harassment, and she needs to know how to deal with it and have the confidence to say NO.
With both of my DC, I've made it clear that if adults or other people them uncomfortable, say things that seem too personal/inappropriate, touch them, or ask them to do things/go placse with them, it's 100% okay to say NO and/or to run away, or ask someone else for help. I can talk to them about this without discussing detailed sexual matters. DD, for example, udnerstands that sometimes men can be a little odd and like to get a bit too close to girls/teenagers and that really, that's not okay, and if it happens, she should shout or run away. We emphasise that most people are normal, kind, caring people, but that there are enough of the ones that are a bit off that she needs to know.
Both DC did martial arts when younger and the teacher was very firm on teaching them that they had every right to bodily autonomy and to feel comfortable. His self defense lessons prioritised running if they were uncomfortable, or going to another adult.
I've also always encouraged my chidlren to understand that "official" people are there to help - from police to the person working in Sainsburys.
So for your DD, the key thing is that she knows that if anything ghappens she's uncomfortable with, she should speak to the air steward. I'd also recommend aiming for a aisle seat for her.