I need flying type for Omega Ruby and I cannot decide on the better of the two. Both should be holding their mega stones.
Why? Accessibility. You can get it as early as the 4th gym and that is pretty dang early for a Dragon-type. Also Mega-Altaria has a great ability (Pixilate). The only issue is speed ad is easily fixed with Dragon Dance. After one DD, this thing is a monster. Also access to Cotton Guard makes it really bulky. Sometimes, Ice-types won't OHKO it!
In a nutshell: Pick Altaria. Easier to get and great Pokemon
Hope this helps!
While you may get bagon late :( he's totally worth the wait. Mega salamance has airelate so yeah stab double edge, hyper beam, giga impact. He also has more bulk then altaria andway better attack. You can use both but if you do center Altaria to special attacks and fairy moves, so basically give salamance 2 dragon moves strength and normal move. Give altaria 2 fairy moves fly normal move. Hope I helped.