Airfreight you want a box that will survive handling. they get tossed around, thrown to handlers off the plane, dropped on the apron and more. Typically a plastic baggie wrapped around with a fragile sticker is not going to be noticed. You need at a minimum a double layer cardboard box, and the inner parts should be wrapped and taped so they do not rattle, with sharp edges ( or basically any corner) being protected with a taped on, or wrapped on with pallet wrap, cardboard edges. Then you place all parts in the box, fill empty volume with either packing foam or an expanding foam pack, then tape the box securely on all seams and wrap again with pallet wrap. Include inside a printed paper describing the contents, and sender and recipient contact details including phone numbers and physical addresses, and duplicate on a paper taped to the outer box as well, under the wrap. Then the documentation is placed in the supplied document pouch stuck to the parcel.
May seem like overkill, but I did do a lot of handling of stuff that had to go airfreight. Biggest thing I posted to myself was a washing machine.