CSA Czech Airlines (OK, Prague Ruzyne) has retired its five B737-500s by January 14 when it has operated its last scheduled B737-500 flight on behalf of wet-lease customer Belle Air (LZ, Tirana) from Tirana to Prague Ruzyne one day after its last own scheduled services. The remaining five B737-500 had an average age of 20.5 years. CSA's fleet now consists of four ATR 42-500s, four ATR 72-500s, nine A319-100s, four A320-200s and two A321-200s.