Matt, if you can imagine a section of aircraft skin finally being freed from the superstructure it was once fastened to then it would be at the mercy of the tides/currents/storms etc...
Being lightweight and thin by it's very nature plus, a large area in comparison to it's thickness, it would not take much to set it on it's way.
The main problem with sections of aircraft skin being washed up on the Pacific Islands during this era is that WW2 was raging and there were an awful lot of aircraft around at that time in the Pacific theatre of operations. So a lump of aircraft skin turning up on an island could have come from hundreds of sources. If WW2 hadn't got in the way (bad timing) then a lump of aircraft skin being washed up on a Pacific Island during this era would have stuck out like a beacon.
That's just my opinion of course and, is open to debate (no more discussions on philosophy please, try and keep the thread on topic)
To recap:
WW2= lots of sources of wreckage
No WW2= one source of wreckage?