Defensive Core For Mono-Flying
Sets:
Infernus (Mega-Charizard X) @ Charizardite X
Ability: Tough Claws
EVs: 224HP/ 252SpD/ 28Spe
Careful Nature
-Will-o-Wisp
-Dragon Claw
-Flare Blitz/Fire Punch
-Roost
Railgun (Zapdos) @ Leftovers
Ability: Pressure
EVs: 252HP/252SpD/4Spe
Calm Nature
-Discharge
-Toxic/Heat Wave
-Defog
-Roost
Tutankhamun (Landorus-Therian) @ Leftovers
Ability: Intimidate
EVs: 252HP/252Def/4Atk
Impish Nature
-Stealth Rock/Stone Edge
-U-Turn
-Knock Off
-Earthquake
Icarus (Skarmory) @ Rocky Helmet
Ability: Sturdy
EVs: 252HP/252Def/4Atk
Impish Nature
-Stealth Rock/Defog/Toxic
-Brave Bird/Counter
-Roost
-Whirlwind
Core in detail: Skarmory and Landorus-T are the physical walls, while Charizard X and Zapdos are the special walls. I'll explain the sets step by step here
Mega Charizard X- This set takes advantage of the amazing typing Charizard-X has. With a bulk of 78/111/85, it's weak to Ground, a type which the other members of the team is immune to, Dragons, which can be played around (More easily if you use a togekiss) and Rock, which is mostly physical and you have two great walls of rock types in Landorus-Therian and Skarmory. Also, it can tank ice beams, which this core is weak to. Will-o-Wisp cripples the physical attackers (Reks Bisharp and Mega Mawile), and the EVs make is Specially Bulky which makes it
really difficult to take down. As for the speed EVs, it really depends on your team, on how much speed you want to run. Dragon Claw is the usual STAB which hits hard on many things, since it takes boost from Tough Claws. Flare Blitz OHKOs many things, such as Mega Gardevoir and Nidoking, but the HP loss sucks, so Fire Punch can also be used. Using Roost ensures the Zard's longevity and it becomes really hard to take down for certain types.
Zapdos- SpD Zapdos walls many of the special attackers in monotype. With a bulk of 90/85/90, it is a really annoying and superb wall against many types. It tanks Electric attacks like a boss and covers the weakness in electric. Discharge hits hard coming as STAB from a base 125 SpA, which can also parahax faster opponents and scarfs (and watch them rage). Heat Wave hits steel types hard while Toxic destroys the longevity of many mons. Defog is mandatory on Zapdos because 1. Flying Monotype. 2. Charizard. Roost helps Zapdos stalling. Best special wall of flying right here.
Landorus-Therian- This is the set that abuses it's ability. With a bulk of 89/90/80, the stats look not impressive from here but with Intimidate, it's capable of survivng almost all physical attacks and hit hard from a Base 145 Atk stat.It tanks Rock type attacks which removes the rock weakness . U-Turn helps keep the momentum, Knock off removes the foe's precious items, Earthquake is the powerful STAB and you can run Stone Edge to give the EdgeQuake coverage or Stealth Rock to set hazards.
Skarmory- Flying's best physical wall. With a bulk of 65/140/70, it can tank physical attacks like a boss and either hit with Brave Bird or Whirlwind them away. This is basically a Landorus-Therian with reliable recovery. Defog gives another chance to remove hazards once Zapdos dies, while Stealth Rock gives Landorus-Therian a chance to use 4 attacking moves. Brave Bird is the strongest attack Skarmory gets, with a little drawback. Counter is a surprise attack which can destroy many threats such as Bisharp, Mega Mawile, Mega Gyarados, Dragon Dance Mega Tyranitar, Mega Medicham, Swords Dance Mega Garchomp, Dragonite, Mega Salamence, Mega Charizard X, Darmanitan, Victini, but if you run counter you literally have nothing against special attackers and if the opponent knows you carry that you're dek'd. Roost gives it reliable recovery while whirlwind wrecks set up sweepers attempting to set up on it.
Good teammates: Togekiss (Heal Bell support), A fast scarfer like Thundurus-Therian or Staraptor.
Threats to the core:
This can ice beam through your entire team and destroy it. If it's scarf ninja (Which is getting more used nowadays thanks to a certain Dark type user), it can destroy the scarfs in your team as well.
How to beat it: If it's not scarfed, OHKO it with Scarf Thundurus-Therian or Scarf Staraptor. If it's scarfed, it lacks the power so Zard X can wall it easily and kill it.
This can set rocks and make it really difficult to switch into anything. Fire Blast kills Skarm, Ice Beam kills Landorus, Stone Edge kills Zapdos and Zard.
How to beat it: Landorus can hit hard with EQ or U-Turn and switch to Zapdos, Ttar usually doesn't carry Ice Beam so Landorus is the way to kill. If it has ice beam, staraptor or a shaky focus miss from Thundurus-T will kill it after weakening it.
One word: Gravity.
........
Also some Landoruses carry Rock Slide and destroys the core.
How to beat it: If it has gravity, sack the least useful pokemon in your team. Since you'll only see gravity in Ground, sack Charizard imo. Then go to a scarfer and kill it. If it has Rock Slide, it will switch in to your Zapdos. Roost the first turn and see if it has rock slide or not. If it does, switch to skarm, then switch back to a scarfer as it will focus blast, then kill it.
And lastly, these things
Why is Kyurem-W even in monotype? Idek. Anyways Sub Kyurem-B destroys what flying has to offer, ice beaming and fusion bolting everything to oblivion. Kyurem-W, on the other hand,
sweeps with the scarf variant, OHKOing almost everything with ice beam.
How to beat them: Kyurem-Black: If it's scarf set, Toxic with Zapdos and then roost stall, or make it use Fusion Bolt and use Lando to hit. If it's Sub, sack something, go to Skarmory and whirlwind it, and next time be aware of the sub and attack it. Focus Blast with Thundurus-Therian or Close Combat with Staraptor hits it hard then go to Zard to kill.
Kyurem-White: Welp, gg. Jk most are scarf, go to zard and tank an ice beam, roost, it will switch out, continue this and if it switches into zard, switch to togekiss because it's gonna draco meteor. Focus Miss from scarf thundy and Close Combat from Staraptor gets it.