Bring an Extra Valuables Bag With You
Pack an extra bag in your carry-on bag in case you need to check it so you can store your valuables in the extra bag (and under the seat in front of you). If your bag is too big to fit under the seat in front of you, you may need to check it at the exit.
You never know when an airline might lose your luggage, so you should always keep important items – like medicines or a camera – with you. Use an extra bag to always have access to your valuables. Plus, you can use it to keep your weight off .
Reminder: Never Put Valuables in Checked Baggage | Conde Nast Traveler