This is disappointing news at best, but in all honesty does contradict some of the things Jes told me a while ago.
That's not to say that things haven't changed since then as it was a while ago, but some of Stick Monkeys earlier posts on this release also contradict what I have heard.
Jes told me that the Dark Eldar fliers (or at least one of them) were already completed, and that was a couple of months or so ago, and he said the guys in the studio "were running around with them making aeroplane noises".
Of course these could have been Betas that haven't been passed through, but I doubt very much that a project get this far only to be pulled. It is more than likely it will be pushed back though, after all GW haven't anounced it yet.
I have been told that there will be 7 releases for this though, so not as many things as SM mentions earlier above.
Best guesses are:
Space Marines: Storm Raven
Dark Eldar: Void Raven/Razorwing
Eldar:essentially same as Dark Eldar kits but more "Eldary"
Imperial Guard: Hydra
Tau: Initial thoughts wer Barracuda, but now this seems more likely to be the Remora
Tyranids: Harpy (if you go way back to one of my threads you will see that we saw Jes and the design team discussing this in Bugman's about 2 and a half years ago!)
? I don't have anything on the last one, most people believe Ork Fighta Bomba, but I haven't heard anything on this.
I can pretty much confirm (although will no doubt end up with egg on my face) that there is no Thunderbolt or Lightning coming, the IG release will be the Hydra. And obviously no Thunderhawk, Marines have the Storm Raven and the scuttlebutt is that with the flyers expansion all Chapters will have access to them.
As always rumours are subject to change, but I have these on good authority.