IVs vary from Pokemon to Pokemon. It is not like some Pokemon definitely have better IVs than others. For example, a Sunkern can have all 31 IVs in all six stats and something like Aegislash or Ash-Greninja or any Uber mon can have 0 IVs in all six stats (Most legendary Pokemon caught in the wild have at least 3 perfect IVs but I'm talking about breedable Pokemon, or on PS!).
Thus, any Pokemon with a compatible egg group is fine, as long as it has good IVs. This unfortunately is generated at random, and you have to really lucky to have perfect IVs in the stat you want.
The gist of what I'm saying is, it doesn't matter which Pokemon you use, because even a Pokemon with crappy attack is still useful in breeding if it has perfect (30 or 31) IVs in the Attack stat. So, you just have to check which f your Pokemon from the same egg group as your Aerodactyl have perfect or near perfect IVs in Attack and Speed. Generally, it is a bonus if it has good IVs in Hp and both defenses too, for maximum survival. Having perfect IVs in Special Attack is a waste as far as Aerodactyl is confirmed.
tl;dr : IVs are independent of species of Pokemon, they are unique to literally every Pokemon, in the sense a Pokemon can have any IV in any stat independent of its stat or total. Look for a Pokemon with perfect IVs in Attack and Speed for Aerodacytl
Finally, get it to hold a Destiny Knot, to ensure (or at least, vastly increase the chance) that the baby Pokemon gets the IVs in the stat you want.