Zagros Airlines, Abadan, Iran, founded 2006. - #1 and #2:
Zambia Airways, Lusaka, 1967-1994. - with thanks to Gerd Clemens - #3:
Zest Airways, Pasay City, Philippines, founded 2008 by renaming from Asian Spirit 1995-2008 (q.v.).,
merged 2013 with Air Asia Philippines to Air Asia Zest.
#5, and - with thanks to Dr. David Bradford - #2a:
ZOOM Airlines, Ottawa, Canada, 2002-2008. - with thanks to Gerd Clemens - #1: