Which is longest Oceanic crossing for any commercial flight route?
For the longest  Oceanic Crossing, the following are the top three contenders:


Sydney to Vancouver
Melbourne to Los Angeles
Auckland to Vancouver


Out of this, 1 and 2 pass over a few islands on their way, 3 does not pass over any landmass.

Have a look at this : www.gcmap.com

Image :


(Image Source: www.gcmap.com)