Question

It is said people cannot walk in space. They just float in air. Why?

Answer 1

As there is absence of gravity which is necessary to walk.

Answer 2

Well people float in space because there is no gravity. It is a special case of gravity called microgravity as said by NASA. Microgravity is a condition in which  people appear to be weightless and the effect is they float! A bright example is that the astronauts float in space.