Planes Around the World

Puzzles -> Measuring Puzzles

You intend to fly non-stop around the world.

But you can only go halfway around the world on a full tank.

However you can arrange many planes exactly like yours to assist with refuelling.

Assuming refuelling can be done midair, ignoring refuelling and turning time, and without crashing any plane, what is the minimum number of planes you will need?

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-\./^\./-

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