A Pelican case for that kind of gear is a bit excessive. The mask needs no more than the protection afforded by the plastic box it comes in. Put the mask box in your regular checked bag or carry-on bag. As others have said, a dive computer should be carried with you onto the plane, as it is an expensive item to risk being lost or stolen. As for the knife, well, as others have said, you don't need a knife that big, but if you enjoy having it, put it in your regular checked bag, as it does not need the kind of protection afforded by a Pelican case, either.
People use Pelican cases for large camera gear (which they insure against loss or theft) and for esoteric diving gear that really needs the protection afforded by a hard case. Most other dive gear is durable enough to simply be put in a regular checked bag, in between your clothing items.
People use Pelican cases for large camera gear (which they insure against loss or theft) and for esoteric diving gear that really needs the protection afforded by a hard case. Most other dive gear is durable enough to simply be put in a regular checked bag, in between your clothing items.