Silence fell between the four of them as they looked up at the sky. There was no sign of movement; the stars stared back, unblinking, indifferent, unobscured by flying friends. Where was Ron? Where were Fred and Mr Weasley? Where were Bill, Fleur, Tonks, Mad-Eye and Mundungus?
Harry Potter and the Deathly Hallows
I'm not sure how to understand "unobscured by flying friends" in this context. I don't really see anyone flying here. I'm kind of confused.