Uniform flag patches are approximately 3 - 4 inches depending on style and can be sewn on or glued on using fabric glue.
Flag patch - Wikipedia
Reverse Field MultiCam/OCP Army Flag Patch w/velcro, American Flag
Recycled Plastic Flag Patches $1 Donated – Flags For Good
Tactical USA Flag (Black) Embroidered Patches (2 Pack) - 2x 3
52700 LARGE SPECIAL FORCES FLAG PATCH
Tactical USA Flag Patch with Velcro Backing
Military Flag Patches: Infantry Branch – CPGear Tactical
Flag Patch (Large) – Flag Matrix
Flag Patch (Large) – Flag Matrix
Thin Silver or Thin White Line Canadian Flag Patch (8 cm x 4 cm