Some items cannot be taken onboard an aircraft as they have the potential to be used to harm other passengers and crew. These include:
If these items are identified, it is likely they will be taken from you. Airports and airlines are under no obligation to store or return the item/s to you.
If you are unsure if an item is allowed onboard, check with your airline or leave it at home. In some circumstances, you may be able to pack the item in your checked baggage, but you will need to check this with your airline.