Two pieces you can print to assemble the TBS FPV racing flags out of cheap, off the shelf available parts.
The first part joins the flagpole and the flexible top. The other part allows you to attach to the flagpole and pull down the and stretch the flag's fabric (optional, actually).
Parts needed for assembly:
1x PVC Tube, 2500mm length (2.5m). Max outer diameter: 20mm (3/4 inch) - flagpole
1x PVC Tube, 1250mm length (1.25m). Max outer diameter: 10mm (3/8 inch) - flexible!
1x steel rod about 50cm long to hammer into the ground
1x TBS FPV Racing flag, available here in 2 designs: