An airstrip shoulder-bordering surface arrangement for extending the width of existing runway and taxiway shoulders comprising a flexible water-impermeable surfacing material extending laterally of a side edge of an airstrip shoulder, an artificial grass surface adjacent the water-impermeable surfacing material, and an edge-fastening system for securing the surfacing material in position relative to the airstrip shoulder to prevent water migration therebetween, the surfacing material having a relatively smooth top surface.