Can a care package land outside the white or blue circle?
One Redditor tested 100 care packages and said that it is always in the circle:
The cargo plane will always drop its loot somewhere in the circle.
Later on, someone said that the plane drops it in the circle as it was when it was flying over, however the circle may shrink in that time, and cause the crate to be in the blue area (I believe I've witnessed this before in game):
Worth noting is that it drops within the circle as it is when the plane starts flying and thus can end up in the blue.
One YouTube video showed a care package land out of bounds in the water, but it was technically within the play circle. The package was unreachable. Note that this video was recorded in May of 2017, so this may have been patched. This video was cited in this Reddit post.