Thanks for the replies!
We now have 2 differing answers, reply #2 and Reply #5
I ask the question because I thought they were the same (Red Port, Green Stb)
I was watching a plane last night, it could have been an Airforce plane, flying fairly low, down the coast, close enough to hear it, but it was dark, so I couldn't see it in detail, (maybe the last surviving Hercules.)
The RED light was visible, the plane was heading south, and was east of where I was sitting, and out over the sea from where I was sitting. (I live on the east coast)
If the protocol is the same for aeroplanes as it is for boats, this thing must have been flying backwards.
Mick