Actually, there are dozens of islands between North America and Hawaii. The
problem is that they are all within a few miles of the North American coast.
They run up and down the Coast. The one I am most familiar with is about
100 feet offshore. Down in California, some of the islands are a dozen or
two miles off shore.

If you were a really good helicopter pilot and planned well, you might be
able to follow one of the shipping lanes with a diesen powered helicopter
and bargain diesel from the ships crew - if you can find a ship spaced ever
few hundred miles.

In the Dole California-to-Hawaii air race, at least one airplane was denied
entry into the race by the FAA because the calculated fuel (using the
pilot's numbers) was only sufficient to get a bit more than half way across.
The pilot said he was expecting tail winds to make up the difference.

It does not take a lot of intelligence to bring up a map and look to see if
there are any islands on the way. That is what the marines did when they
invaded Grenada. They went to the local travel agent in St. Georges, once
they landed and got all the maps they could get their hands on.