Cameo blimp

Early yesterday morning a bright blue blimp appeared over the Sydney Cricket Stadium.  It hovered over the area for 10-15 minutes then disappeared without warning.  Garry says he's spotted it several times earlier in the week. Howver, it's never reappeared leaving us unsure of its ultimate purpose.  A logo of Bayer, the multinational phamacutical company, is printed on along one side so we can only assume it was part of an advertising shoot.