Doesn't look like photoshop material to me. It's not very rare to see these scenes if you're an airline pilot. It really just depends on how beautiful the photo is, in this case this photographer's photos are too good to believe.
Airliners.net doesn't accept fake photos as far as from what I know of, if you could find any evidence that the photos are fake, please point them out. I'm looking forward to what evidence you will find. If you fly as much as an airline pilot, passing over another plane is a very normal thing. Most of the time when you're on a aircraft travelling you won't look out the window much and therefore even if another aircraft is over or below you, you'd have no idea. How many times do you look out the window? Not as much as airline pilots. They have to observe everything and because they have a larger view, they will spot a lot of things you don't spot.
Cheers