Even worse for Deidara, since he's not used to pressure of this level once he is in the air. Sasuke managed to reach Deidara with a simple chidori spear and glide, Kakuzu has his threads, and his masks that he can use to propel himself, nothing is stopping him from bringing Deidara back down.
Sasuke only reached Deidara because he was on that Dragon which has 0 mobility[
You must be registered for see links
] If that had been Deidara standard bird Sasuke would have never got to land an attack nor would he even be able to reach anywhere near it's heights[
You must be registered for see links
]Deidara had to be atleast 1 thousand feet in the air here. Kakuzu propelling himself would result in lack of mobility in the air which would make him and even easier target. He's never going to be able to catch Deidara while he's that high in the air plus his evasive feats that dodge Gaara's sand which is fast enough to counter a bloodlusted Ei. If they jump into the air multiple bombs can attack them from the front and back or at there legs. We've already seen how easily the birds managed to get around Gaara's sand attacks and attack him[
You must be registered for see links
].
Deidara is never getting overwhelmed here. The mask aren't fast enough Kakashi manage to dodge the fuuton mask and make it in-front of the raition mask streams on foot. Deidara flying speed>Kakashi foot speed. All Deidara need to do is make a doton clone put it on a bird while holding the small c3. Once the clone gets in range within Kakuzu Deidara activate c3 to blow him to dust.