Question

Does light travel faster in air or in space?

Answer 1

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Answer 2

Light always travels its fastest in empty space. Or a vacuum, or a void, whatever term you prefer.
The molecules of any medium only get in the way of it propagating fast, and slow it down at a ratio called refractive index. For air, it is 1.0003. That is to say, light travels 1.0003 times faster in a vacuum than it does in air