What is an example of a hypothesis that Aristotle had that was later proven to be incorrect?

Spontaneous generation / abiogenesis

Explanation:

Long ago, philosopher still debating where did living organism come from. Aristotle came up and hypothesized that living being can come from inanimate matter (without any genetic transfers from the parents of that particular organism). This theory called spontaneous generation.

Spontaneous generation had later on proven to be false and living being is not spontaneously created, but come from reproduction of the same species which passed on their genes to the next generation.