The Insect Glaive is perhaps the most unique weapon in all of Monster Hunter.

As a weapon it is comparable to the Dual Blades, Longsword, and Sword & Shield. It's a fairly fast weapon that deals slashing damage. The Glaive has no range and no shield to assist it. As a weapon, it's a fairly simple polearm.

There are three things that make the Glaive unique, however:

1. Bugs. The Glaive is the only weapon that has a Kinsect. A bug companion. This is equipped as a second weapon and will inflict damage and produce dust. Kinsects extract essences from monsters and will deal damage. In fact, the Kinsect's damage mechanics make it strong against Alatreon.

2. Essence. The Glaive has three types of essence, obtained from using the Kinsect to strike monsters. There are three types of Essence (Red, White, Orange) and they are generally attained from hitting the Head, Wings/Legs, and Body respectively.
Red Essence is the only type of Essence that matters in this guide. When you have Red, you get access to a different moveset. This applies both on the ground and in the air.

3. Air. The Glaive is the only weapon with a Launch move. Other weapons can get into the air, but the Glaive has got an entire moveset for when it is airborne.

Most guides will tell you to ignore the last one. That you shouldn't be in the air at all. They're not completely wrong, but this guide will help you learn how to use the air as your ally.

The Glaive has got 6 different attacks in the air as of Iceborne. Before Iceborne, the Glaive had 5 attacks.

But first the Vault.

Vault is a very simple move. You launch yourself up in the air like a professional pole jumper. You stand the Glaive on its end and propel yourself high. This gives you a decent amount of height (easily on level with most wings). If you're getting into the air, you're Vaulting.

For our first attack, you've got the Descending Thrust.

The Descending Thrust stabs straight down, propelling you to the ground while dealing damage. When you land, your character will do a swing similar to a grounded mark attack. This is similar to the Kinsect (Mark Target) move on the ground, except with a stronger slash.

This move can be very dangerous to use at the wrong time! The grounded portion of the Descending Thrust will keep you locked into a move animation. It can potentially be decent at dealing damage if used correctly but it's risky.

Second, you've got the Claw Grab.

Your character instantly stops what they are doing and descends. If you come into contact with a monster, you will grab onto it as if you had used a claw shot. When landing, there's an animation where you strike the ground.

This can be used to soften up your target and do a flinch shot or however you want to use the claw. There are far better claw guides up there. For the most part, you can ignore this attack. Use it as part of your general claw strategy.

The next thing you can do in the air is Evade.

The 'Evade' move is just like your grounded rolling. You can change direction, you can avoid an incoming attack. This move is largely about aerial mobility. This allows you to change directions on the fly. Literally on the fly, as you're flying!

From a Vault, you can use one Evade. You can Vault, Evade, Attack. Notably, you can change direction with both the Evade and the Attack. This allows for some interesting aerial manoeuvres.

And now for the two real attacks..

Remember how earlier in the guide, I mentioned Essence and how Red is the only one that matters? Well, that's due to how it alters the moveset.

You have two real attacks, either with Red or without Red. With Red is stronger, without Red is weaker.

No Red Jumping Slash

This is the worst move in your arsenal.

You do a mediocre slash. It does about the same damage as a grounded thrust. You're locked into the animation no matter what when you do this move. You can't evade or do another attack until you hit the ground.

If you're close to the ground when you use this, you will hit the floor with a longer landing delay. If the move completes in the air, you've got nearly no landing delay.

This is only ever used to finish an aerial attack sequence.

No Red Jumping Advancing Slash

There are two things in this move that make it useful.

First, it's like a second evade. You can change directions in the air by using this move. Even if you're just wanting to get up a cliff or something, this is practically a triple-jump. Vault->Evade->Advancing gives distance.

Second, when you hit a monster you will launch with a vault.

This means that you can stay airborne for ages. You can extend your time in the air by using this move. If you want to have some fun, go find some Vespoids and try hitting them with this. See how many you can kill while airborne.

You can nearly infinitely combo Vault->Advancing->Aerial Vault->Advancing

(Don't)

With Red, Strong Jumping Slash

Without Red, Jumping Slash does one slash in the air. It's mediocre, it doesn't hit much.

With Red, Jumping Slash does a long descending twirl that hits multiple times. You get landing delay, but you can easily hit 3-4 times with this attack. This will always take you to the ground but it's your main way to land from an aerial sequence.

Strong Jumping Advancing Slash

This is the main Aerial move. This is the one that people use.

You advance, just like with the non-Red version, but you twirl the Glaive around your body. You're striking repeatedly with little bites, only slightly stronger than your Kinsect. When you finish the move, if the last attack hit then you will vault up in the air.

This move is the one you're thinking of when you think Aerial Glaive.

This is actually quite fun!

First, you can have no essence and find some Vespoids or other small monster. Advancing Slash works on these small creatures, so you can take them down while jumping between them. With fast-respawning areas, you can keep this chain going so you'll never hit the ground.

Spider-Glaive

The Glaive sticks to climbable surfaces. If you Vault->Evade into vines or any climbable surface, you will stick to the wall. From here, you can do a leap move up the wall. Or spring off it and evade right back.

This is slower than climbing normally for most cases. With big vines, you're better off just climbing like normal.

Most vines are not big vines. They are small.

The Glaive can use Vault to climb up smallish ledges without needing to go through a climbing sequence. Vault->Evade->Advancing Slash can give you enough air to clear some ledges without needing to put away your weapon. When you're seeking height advantage in a fight, knowing about these ledges can be useful.

When you're not in a fight, vaulting this ledges is just more fun than doing the vine animations.

Ice Climbers

Hoarfrost Reach is a fun location. At the back of the map, there are some grappling points that lead to a big mountain obstacle course. This is a fairly involved obstacle course that involves a lot of wall jumping... For non-Glaives.

Due to sticking to the walls and the aerial mobility, the wall-jumping sections are turned into just a simple Vault->Evade and then climbing up at your leisure.

The part where this is really fun is with the steam geyser.

Normally, this can be annoying to deal with. With the Glaive, you can just run up and Vault->Evade->Advancing Slash to land on the ledge without dealing with the challenge. You feel like you've cheated the system when you do this.

Don't use Aerial Glaive exclusively.

The biggest, biggest tip I can give you is to focus on grounded combos. For 90% of a fight, you're focusing on your grounded combos.

Aerial Glaive lowers your DPS by an extreme amount. It's better to learn everything on the ground, not in the air.

I cannot stress this enough. For 90% of a fight, you're going to be on the ground like a good fighter.

For the other 10%...

Despite losing DPS, there are some key parts about Aerial Glaive that makes it a useful tool to have under your belt. It is just one tool in your belt, not the entire belt.

Wings

Very few weapons can really break and damage the wings/back of monsters. Safi'jiva in particular has a back breaking advancement that's nearly impossible with most groups.

The Aerial Glaive can be used to deal damage to the wings and back with ease. When getting those rare membranes, remember that Aerial Glaive can collect that material easier than grounded Glaive.

This does apply to scalping Shara Ishvala as well.

Sharpness

So, deflections exist.

Monsters have parts that are armoured and will deflect your attack without the right sharpness. Even with Purple, you're going to have some deflections on some monsters. Half the fight with Lavasioth is about weakening the stone armour.

Aerial Glaive doesn't deflect.

You cannot be deflected when using Aerial Glaive

You can have Orange sharpness and still hit a Rajang's forearms as if they were a Vespoid's wing. No deflections at all. Don't, it's stupid, but you can.

Temporal

The Temporal Mantle auto-dodges when you get hit. This interrupts a Great Sword's big True Charged Slash. This interrupts all grounded attacks.

When airborne, you get the dodge but none of the movement.

It's like you just ignore the attack entirely. You will continue that advancing spinning attack. You will just lose some time on your Mantle, but otherwise there is no difference between the monster attacking and standing around.

I cannot stress this enough: In multiplayer and in general, you want to limit your time in the air a lot.

You do more damage on the ground. Your teammates will get annoyed if you're just some buzzy bee doing chip damage with an Aerial Glaive. Your Palico will even be disappointed in you. Your Moogle will be disappointed in you.

The Handler will out-DPS you.

Resource-Gathering

When you're collecting those wing materials or that back siege objective, the Aerial Glaive is useful. You get to deal damage to the hard to damage places.

Piscine Wyverns

Water sucks. It slows you down and unless you have Mirewalker, you're going to have a bad time.

With Aerial Glaive, you can approach and chase after the Piscine with ease. No need to ignore the water or try to get him to land, you can approach and deal some damage while out of the water. This also applies to the ice version, though it's less important there because of the Ice Mantle.

Approaching

Okay, this is the main time to use the Aerial Glaive.

Strong Jumping Advancing Slash is a strong attack. It advances, it slashes. It's a flea bite, but it's more than walking.

In a fight, there are often times where there's a good distance between you and your opponent. Where you can't easily approach, or that you have to do a lot of chasing.

The Aerial Glaive allows you to approach while dealing damage. It's a way to close the gap in a fight. Monsters also struggle to track you while you're doing this. Combined with Evade, you can change directions and approach and follow the target.

You just want to do a single Strong Advancing, then ground yourself with the Claw, Descending Thrust, or Jumping Slash. This can get a bit more damage in where otherwise you'd just be walking.

Mounting

The main thing people use Aerial Glaive for is mounting. You can easily mount a monster and topple it. When you're using your aerial attacks, there's a fairly good chance you will mount the beast.

When its toppled, you can also jump over the monster to get to the weak spot you're targeting. It's a DPS loss, but at least it's DPS while moving around. It's often faster as well.

Toppling monsters like this is the main reason people will get into the air. It's a way to get some free damage in, do your best combo as a team, and strike with impunity.

Using your Jumping Slash rather than the Advancing moves is a lot better for mounting. They have a higher chance of giving you the mount. This can effectively let you choose when you mount.

Don't Aerial Glaive exclusively.

Use it as a tool that you use. Don't be afraid to take to the air every so often. It's fun, and probably why you chose this weapon in the first place.

It shouldn't be your main focus, it should be just another tool in your tool belt.

I have nearly a thousand hours of gameplay with the Glaive and even I struggle with the balance of when to take to the air and when not to. My friends know I can use it well, randoms not so much.

And don't, whatever you do, don't use the Aerial decorations. They're not worth it at all.