Wow so pretty much, his mega evolution provide higher attack stats. to make it as strong as aerodactyl with life orb? but the benefit of mega aerodactyl, is to use coverage moves? hmm
Aerodactyl's Mega Evolution makes it an excellent revenge killer in conjunction with its wide movepool. I also forgot to mention that its bulk is pretty good for an offensive Pokemon, provided you get priority it's weak to (Bullet Punch and Aqua Jet) out of the way.
Regular Aerodactyl, on the other hand, is pretty frail.