The Na Pali Coast of Kauai, with its massive sea cliffs, is a simply spectacular sight.
While the new-at-the-time Canon EF 24-70 f/4 L IS Lens was my primary standard zoom lens for this trip, I used the 24-105 L IS from the helicopter. I made this choice primarily for the longer focal length, but in the end I decided that either lens would have worked very well.
I used a B+W circular polarizer filter in 100% of my helicopter aerial photos on this day - an XS-PRO Nano version in this case.