These two nouns are pronounced the same but have very different meanings. An aisle is an indoors path that is part of a larger space, such as the paths between shelves in a supermarket, between the seats in a cinema, or lanes between ropes, such as in the customs area of an airport:
During the pandemic people tried to avoid each other in supermarket aisles.
An isle, on the other hand, is simply an island:
She dreamed of living on an isle in the Caribbean sea.
However, isle has somewhat archaic and romantic connotations, and is usually used only in predictable ways. In most cases, the safer usage is island:
They were shipwrecked on a deserted isle.
It was called “The Isle of Lost Toys.”
They built a house on the isle.
When in doubt, use island instead of isle.
The real estate agent showed them a house on the island.