Mit has correctly identified the Aero L-39 Albatros ZK-TCS wing tip tank.
ZK-TCS2 c/n 131848, was listed to The Copter Shop Ltd (hence TCS) of Nelson on 05-01-07 and was removed from its container at Helicare Servcices at Nelson Airport on 26-02-2007.
It arrived in its full previous operators colour scheme.
The above pic was shot by Matt Hayes. The lower shot taken during its first flight in NZ was captured by Peter Campbell on 27-10-2009.