What is the difference between 에 and 을/를 when used in these three sentences
하늘을 나는 기분이었어요.
I felt as if I was flying in the sky.
What about if I use 에 instead? What does it translate to?
하늘에 나는 기분이었어요.
하늘에 새들이 날고 있어요.
Birds are flying in the sky. (translation taken from a book)
(Is the translation right for this sentence, because when I use 에, I picture going to it. Like 집에 가요. I go to school. So, 하늘에 새들이 날고 있어요. I picture birds flying to the sky, not in the sky.)
What if use 을/를 instead? What does it translate to?
하늘을 새들이 날고 있어요.
하늘을 날고 싶어요. I want to fly in the sky.
하늘에 날고 싶어요. (What does this translate to?)
Thanks in advance,