Is Altaria good with Mild nature and Cotton Guard?

Question

I am playing Black 2 and I want to have Altaria as my flying type and also for using Fly(HM).
My Altaria is going to be basiclly Special and will use Fly only for STAB.
I have got two Altarias one has Mild Nature and another has Timid Nature.
1)I can either go with the Mild one and use cotton guard for filling up defense.

                                                                       or

2)I can use the Timid one and compromise on the power of Fly(That will be my only Flying move for it)
I am planning this moveset for it:
Dragon Pulse
Fly
Flamethrower
Cotton Guard for Mild/Ice beam for Timid

Comments

Timid all the way, since you're not going to be using Fly as much as the other moves in battle anyway.

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If this is ingame then don't use cotton guard

Answer 1

Timid

Why? You're not going to be using Fly much in battle so you're better off with the Timid Altaria. Another option is to just out it into your party when you need Fly and take it out when you don't need Fly. Also, ingame Cotton Guard would be pointless as the AI us next to useless.
Hope this helps!