Aerodactyl in Metagamiate is a nasty customer, able to either run Double Edge+Rock Head (Regular Aerodactyl with a Sash) or Return/Frustration as Mega Aerodactyl, and either way it hits really hard with a no-disadvantage 100% accurate Rock move while outspeeding most of the meta. The result is sufficiently far ahead of Aerodactyl's other moves -particularly for Mega Aerodactyl, which has nothing else that is STAB+Tough Claws boosted let alone is an -ated move off a ridiculous base- that coverage is a "nice", not a "necessary". You might as well run Earthquake just to deal with the likes of Lucario (Doubly resists Rock, for one), but you're also more free to carry support moves -Mega Aerodactyl can pull off carrying Roost, for instance, to let it tank Stealth Rock, so long as you're careful to switch it in on one of Metagamiate's crucial walls (Hippowdon, Skarmory) rather than a straight attacker, otherwise you may well die horribly. It is absolutely viable to run something like Return/Earthquake/Roost/Toxic (Toxic for Hippowdon and other, non-Skarmory Physical walls) and still tear through much of the meta. (Though Bronzong will wall you effortlessly, which is in fact relevant, as its immunity to Ground+Rock resistance+Dragon resistance is extremely helpful for walling a lot of the tier's major Physical attackers)
252+ Atk Life Orb Tough Claws Mega Aerodactyl Frustration vs. 252 HP / 252+ Def Skarmory: 187-220 (55.9 - 65.8%) -- guaranteed 2HKO after Leftovers recovery
Look at that! (Life Orb simulates the -ate boost) You don't even need a coverage move for Skarmory, and in fact it's a waste of a moveslot.
Aerodactyl does have its flaws, however. Firstly, it is extremely vulnerable to priority, which is far more common in Metagamiate than in most tiers -Terrakion runs Quick Attack, for instance, which does
252 Atk Life Orb Terrakion Quick Attack vs. 0 HP / 0 Def Mega Aerodactyl: 198-234 (65.7 - 77.7%) -- guaranteed 2HKO
a ton of damage, so Terrakion can revenge Aerodactyl pretty effortlessly -add a Band to the above and you get
252 Atk Life Orb Hustle (Simulating the Band) Terrakion Quick Attack vs. 0 HP / 0 Def Mega Aerodactyl: 291-346 (96.6 - 114.9%) -- 81.3% chance to OHKO
this. It's extremely dangerous to stay in on Terrakion, even though your own Earthquake is a clean OHKO -and there's plenty of other examples out there, such as Extreme Speed Raikou, which Mega Aerodactyl would normally handily outspeed and KO.
Secondly, the Rock typing in particular is less appealing in Metagamiate than in a standard tier for several reasons, for all that it provides the basis of Aerodactyl's impressive offense. After all, only Normal types will be using Normal moves, effectively mooting that resistance, Steel is no longer capped at 80 BP or the odd 90 and instead hits with 132.3 BP moves, not even counting the likes of Rock Head Double Edge Aggron, which is somewhere over 150 BP in effect, so the Steel weakness is considerably more acute, and Water is a very popular type in Metagamiate for offense. (The Fighting, Grass, and especially Ground weaknesses are counterbalanced by the Flying typing, thankfully)
Weakness to Stealth Rock is also a problem, albeit one that Roost can minimize -but a turn spent Roosting is a turn not spent wrecking things.
Lastly, in the event that you end up Paralyzed, unless you have a cleric (Which is extremely difficult to pull off in Metagamiate) Aerodactyl is more-or-less useless, probably only good as a sacrifice. This is more common than you might think, since several Pokemon do in fact run Body Slam -most notably Jirachi (You have no business switching in on Jirachi, but you might think it's safe to stay in when it revenges and it turns out to be Scarfed) who will likely Paralyze you if you even survive, and Togekiss, who isn't going to be KOing you but could well Paralyze you on the switch-in (Even aside from its Thunder Wave access), and is otherwise a tempting switch-in opportunity for Aerodactyl.
There's also the point that Bronzong is difficult to push past. For Mega Aerodactyl this is manageable
252+ Atk Tough Claws Mega Aerodactyl Crunch vs. 252 HP / 252+ Def Bronzong: 170-202 (50.2 - 59.7%) -- 78.5% chance to 2HKO after Leftovers recovery
but this is getting into 4MSS territory, since another use of Aerodactyl is putting up Stealth Rock, and it's not safe to switch in on Bronzong by any stretch of the imagination, unlike most Physical walls.
0 Atk Bronzong Gyro Ball (150 BP) vs. 0 HP / 0 Def Mega Aerodactyl: 336-396 (111.6 - 131.5%) -- guaranteed OHKO
So in summary: it's a holepuncher, but one that can come apart very completely very abruptly.
Sample sets.
Aerodactyl @ Focus Sash
Ability: Rock Head
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Double-Edge
- Earthquake
- Fire Fang/Crunch/Roost/Taunt
- Stealth Rock/Roost/Taunt/Toxic
Aerodactyl @ Aerodactylite
Ability: Unnerve
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Return
- Earthquake
- Crunch/Roost/Taunt
- Stealth Rock/Roost/Taunt/Toxic
If you're running Mega Aerodactyl Unnerve should be your base to block Berry use -Harvest Trevenant in particular is, in fact, a thing, whereas Rock Head is useless and Pressure is extremely limited in use. Stat-boosting berries also crop up at times, usually Speed, and blocking them is legitimately useful. Speed in particular will provide no benefit the turn you Mega Evolve and it is consumed, so that can be useful.
EDIT: Forgot to remove the Life Orb simulating the -ate effect when I calculated Crunch on Bronzong, though it's still usually a 2HKO. Fixed.