Where to put euros on flight

I hope it’s just a little emergency fund and not a ton of cash! If I had to be in this position, I’d put it in various spots in my carryon, not in any luggage I could be separated from, and if she does not know about money belts, find out asap!
Limited cash and a bank card for purchases is the safest course.

It’s pretty rare that she’s going to get “mugged” on her flight. And I agree with the above, limited cash and a bank card.

Does she have a moneybelt? That would be a comfortable & safe place to carry them assuming she has paper money, not coins. Where is she going to study? I remember my daughter spent a semester in Malaga Spain and had to take a public bus every day where she was constantly 'chatted up' by men (evidently it went through a famous sex worker area.) I worried about her of course when she wrote me this (the days before online communications), but she really never had anything scary happen to her. Encourage her to walk like she knows who she is and where she's going

She is not going to get mugged on the plane. I keep my money in an interior zippered pocket of my purse and I keep that under the seat in front of me. I take my purse with me to the restroom.

the airport and the rest of a ground transport journey can be a place to get mugged or lose money, and some of us get flustered during travel especially when sleep is disturbed, so being organized is a must. If she has some toiletry bags and the like, that is often where I’ll stash a bit of cash. But again, I’m never carrying enough money to be worried about losing it.