It was rumored for a long time, but never set in stone that a deal was done. He even had a post that said along the lines "I've gotten word that the deal is done and DL is acquiring 9 more MD-90s."

And as harmless as it is knowing which NW planes are getting repainted, it still is not something that could easily be known. Someone was giving him information..he even knew when planes would be going in the hangar in advanced.

He also knew what planes were in storage like DC-9-30s and if they were sold ( and those are VERY hard to keep track of)