Above and over are the prepositions which usually mean ‘higher than’.
The aeroplane hovered above/over us.
The fan is right above/over us.

But over can also mean ‘covering’, ‘across’ or ‘on the other side’. Over indicates movement too.
There is a temple over these mountains.
There is an old bridge over the river.

The dog jumped over the fence.

Over can also mean ‘during the process’
Let us continue this discussion over a cup of coffee.

Above can also mean ‘earlier’ as mentioned in a book or article.
Kindly refer to clause A mentioned above.