The Kurds are the largest national group without a nation state. More importantly the existing regional powers have found Kurdish nationhood threatening, and major powers like the United States have shared that perspective. Most of Kurdistan is now divided between Turkey, Iran and Iraq, and all three countries have experienced numerous Kurdish insurgencies since 1920.
Smaller pockets lie in Syria, Armenia and Azerbaijan.
There are major communities of refugees throughout western Europe and the United States. Since the 1980s, one of the PKK-related flags has emerged as the principal flag representing Kurmanji Kurdistan. Also since the 1980s another flag seems to have emerged as the most widely used for the region. There is no central authority to legislate flags for Kurdistan, and until very recently most Kurds did not seem interested in any precision about flags. I have some friends who were very close to government officials of the Mahabad Republic , and they insisted 15 years ago that there was no Kurdish flag.