I played a rainbow deck versus a deck sporting Deja Vus paired with SoP, SoF and Mitosis (pretty mean combo!), and to not let them bypass my shield, I used the web ability of both Flesh Recluse and Phase Spider before they parted. When they DID part, the new copy regained the inherited airborne ability.n
To my understanding, the Deja Vu ability should add an exact copy of the creature, but that apparently does not happen.