It's not supposed to be like that and this is the bug. It was overlooked and forgotten for some
reason (GMs deleted it manually after every wipe which, ironically, helped it stay that way).
It's finally fixed on the next update in the map file, so the vertibird will never appear again.
xsarq was lucky enough to come to Navarro after someone regenerated the location but forgot
to delete the vertibird. So he filled it with cells and flew away. He didn't report it. He posted
a screenshot in #2238 channel, which is why it was found out so quickly by staff. He got a few
exciting minutes and an interesting story, he can have his cells back if he contacts me. There
is nothing more to it. The vertibird was not supposed to be there, or in hands of any player.
In my opinion it's enough, if it was some petty item not worth much it wouldn't be a big deal
to let him keep it, but it's not the case. He had his 5 minutes of fun in vertibird that wasn't
supposed to happen, I really see nothing to compensate, except the cells.
About the islands.
At least for now, the islands sometimes have temporary locations for events or testing which
aren't supposed to be freely visited by players. It depends on a location, but oten it's not possible
to hide them because they are public, so everyone will see them as soon as they get close.
Once we add sea travel, something will have to be done about it, but for now it is what it is.
So no player can have a free access to the ocean in the moment.