Packaging machine to make an airtight wrapper comprising a wrapping sheet wrapped airtight around a structured assembly consisting of an organized group of smoking articles associated with a reinforcement insert, wherein said packaging machine comprises, in working sequence on one or more cyclical conveyor devices (39, 71) of the wheel or carousel type: - a structured assembly formation unit, comprising a formation pocket of the structured assembly with a chamber having a lower wall, an upper wall and lateral walls, configured to obtain a structured assembly consisting of the organized group of smoking articles partly wrapped by the reinforcement insert; - a combination unit suitable to combine the structured assembly with said wrapping sheet, with or without a reusable closing label, obtaining an intermediate combination of the wrapping sheet and structured assembly; - a welding station, in which a first folding of the wrapping sheet is made along the longitudinal axis around the structured assembly, with connected positioning welding of respective upper and lower edges of the wrapping sheet, defining a welded transverse edge, to obtain a manipulable whole; - a wrapping sheet work unit comprising a gripping member, configured to work the manipulable whole, and comprising a folding station provided with a folding device with folder means, in which both transverse lateral flaps (26, 27) and also longitudinal lateral flaps of the wrapping sheet are folded, obtaining a pre-wrapper provided with longitudinal layers; - a welding unit, having at least one welding station provided with welding devices, configured to work the pre-wrapper at least in relation to the longitudinal layers in order to complete their welding, obtaining a closed and sealed airtight wrapper; the packaging machine being characterized in that said gripping member of the wrapper work unit has an upper plane subjected to elastic members acting toward a fixed base plane, the upper plane and the base plane being equipped to contain and position the intermediate combination. - a structured assembly formation unit, comprising a formation pocket of the structured assembly with a chamber having a lower wall, an upper wall and lateral walls, configured to obtain a structured assembly consisting of the organized group of smoking articles partly wrapped by the reinforcement insert; - a combination unit suitable to combine the structured assembly with said wrapping sheet, with or without a reusable closing label, obtaining an intermediate combination of the wrapping sheet and structured assembly; - a welding station, in which a first folding of the wrapping sheet is made along the longitudinal axis around the structured assembly, with connected positioning welding of respective upper and lower edges of the wrapping sheet, defining a welded transverse edge, to obtain a manipulable whole; - a wrapping sheet work unit comprising a gripping member, configured to work the manipulable whole, and comprising a folding station provided with a folding device with folder means, in which both transverse lateral flaps (26, 27) and also longitudinal lateral flaps of the wrapping sheet are folded, obtaining a pre-wrapper provided with longitudinal layers; - a welding unit, having at least one welding station provided with welding devices, configured to work the pre-wrapper at least in relation to the longitudinal layers in order to complete their welding, obtaining a closed and sealed airtight wrapper;