Aluminum won’t crack like a polycarbonate shell. You can stomp on these bags and stand on them. Don’t tell airport security, but my daughter and I have been known to race aluminum carry-on bags through airport terminals, like real-life Mario Kart. When frequent travelers buy luggage, they want this structural integrity and reliability. Rigid shells with metal frames and strong latch closures offer better protection for your belongings and should last a lifetime. Metal rivets, high-quality wheels, robust handles, and better components also mean that all-metal luggage is easier to repair. Well-established brands typically offer generous warranties and repair services, especially on premium cases. Clamshell, zipperless closures are also harder to force open; there’s no zipper fabric that you can sneakily slash through with a pen knife. As with all good-quality luggage brands, the majority now use TSA-approved combination locks, which are not only far more elegant than a clunky old zipper, but add to the confidence these cases afford. The irony of making a more sustainable purchase while also burning through aviation fuel is …