Turkey is strange situation. They are (mostly) Sunni Muslims. Religiously all Arabs are Sunni. A minority and those that are not Arabic (Iran) are Shiites. Traditionally they do not get along because of their interpretation of Islam. Think of that as Catholic vs Protestants. Turks are ethnically the same as Indians. They are not Arabs and nothing in common with them other then their religion. So there is a corresponding war going on between Sunnis and Shiites in addition to the war against Isis Syria by the way is mostly Shiites. And ethnically Syrians are not Arabs. Turkey is hostile and fearful of any interference, thus the downing of that plane. Turkey is also reluctant to shoot and kill Sunnis.