It would be appreciated if you could correct sentences below.
It's a summary of "Aloft" by Joe Hill.

A man who has a fear for heights is forced to go sky-diving.
He almost decides to give up when they find a UFO-like cloud, and the airplane's engine stops working above it.
So, he jumps with his jumpmaster harnessed behind him.
However, they hit the cloud hard and his jumpmaster drop out of it, leaving him alone on the cloud.
Then strange things begin to happen on the strangest cloud.

查看翻譯

A man who is afraid of heights is forced to go sky-diving. He is about to give up when they fly above a UFO-shaped cloud and the plane's engines stop working. So he is forced to jump with his jumpmaster harnessed behind him. However after they jump, they hit the cloud hard and the jumpmaster breaks away from him, falling though the cloud, leaving him alone. Then the strange things begin to happen in the strangest cloud.

there are only a couple grammatical mistakes:

"a man who has fear for heights" should be "a man who is afraid of heights"

and "his jumpmaster drops* out of it."

but I've changed it abit because it doesn't make alot of sense the way you've said it, even though its mostly grammatical. let me know if you have any more questions!