http://revach.net/article.php?id=639

Section: Halacha   Category: Tshuvos
Rav Shlomo Zalman Auerbach and Rav Chaim Kanievsky: Is Wearing a Hat For Davening More Important Than Davening With a Minyan?

The Mishna Berura says that a person should wear a hat during Davening because it is not the practice to appear in front of prominent people without a hat.  Rav Chaim Kanievsky Shlit'a says that if a person will miss Davening with a Minyan if he insists on wearing a hat it is better to Daven without a Minyan with a hat than to Daven without his hat with a Minyan. Rav Shlomo Zalman Auerbach argues and he holds although one should make every effort to Daven with a hat he should not give up Davening with a Minyan for it. (Alon Ahavas Shalom)