I have dreamt of my Mom many, many times. She died when I was 21, and she was 44 (she was sick 1.5 yrs before she died, during which I took care of her). Some dreams are very disturbing...in that, maybe they're about reliving her illness/trying to resolve something there. However, other dreams seem to be more airy, more about comfort. I've had a flying dream with her too, which was amazing. I've dreamt about her with things that have actually happened in the past, and I've dreamt about her as if she were living.
I've also dreamt many times of my late cat, Einstein. She was the most precious baby, and I loved her so dearly. She has talked to me in my dreams, cuddled with me, followed me around...just all kinds of stuff.
I can't say what it all means, but I do get something positive about dreaming from those who are no longer here.
Maybe your Dad is telling you that he's always there with you, no matter where you are
.