Rabbi Mordechai Eliyahu and Rabbi Avraham Shapira, the two most senior halachic authorities for the religious Zionist community, gave their backing Tuesday to a potential boycott of El Al Airlines. Rabbi Yitzhak Goldknoph, secretary of the Rabbinic Council for the Holiness of the Shabbat - a body that represents Hassidic, Sephardi, and Lithuanian haredi spiritual leaders - said that the two religious Zionist rabbis had added their signatures to the petition to boycott El Al if negotiations fail. The rabbinic council is still negotiating with El Al to prevent the national carrier from flying on Shabbat. The council demands that El Al management give over to a rabbi the final say on whether El Al can make emergency flights on Shabbat. In the meantime, rabbis are telling their followers not to fly El Al.