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Air springs and their mounts are designed to help support the vehicle weight at a certain height, to help control lean on corners . You would have to modify the mounts to get any lift out of an air spring ( bag ) install.
Air shocks , because they are designed with enough overall length to extend to the full suspension travel may provide the lift you're after; IF ! they are available for your chassis and rated for enough pressure to do any lifting of the weight involved.
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.