How does Cut from the Air interact with Reach weapons?

Question

Cut from the Air

When a ranged attack is made against you or a target adjacent to you, you can cut the weapon (or ammunition) out of the air, deflecting the attack so the target takes no damage. As an attack of opportunity, make a melee attack roll at your highest bonus. If the result is greater than the attack roll total of the ranged attack, the attack is deflected. You must be aware of the attack and not flat-footed. Unusually massive ranged weapons (such as boulders or ballista bolts) and ranged attacks generated by spell effects cannot be deflected.

Could you use it in these cenarios if you have a reach weapon?

1. A enemy 30ft away that you see makes a ranged attack against you.

2. A enemy 30ft away that you see makes a ranged attack against a ally adjacent to you.

3. A enemy 5ft away that you see makes a ranged attack against you.

4. A enemy 5ft away that you see makes a ranged attack against a ally adjacent to you.

5. A enemy 30ft away that you see makes a ranged attack against a ally 10ft away from you.

6. A enemy 5ft away that you see makes a ranged attack against a ally 10ft away from you.

And another question just to clarify "attack at your highest bonus" means the highest BAB plus and minus everything else that you have at the moment like weapon enchantment bonus or power attack right?

Answer 1

You use it like how it says.

Cut from the air is fairly clear about how it works:

When a ranged attack is made against you or a target adjacent to you, you can cut the weapon (or ammunition) out of the air, deflecting the attack so the target takes no damage. As an attack of opportunity, make a melee attack roll at your highest bonus. If the result is greater than the attack roll total of the ranged attack, the attack is deflected. You must be aware of the attack and not flat-footed. Unusually massive ranged weapons (such as boulders or ballista bolts) and ranged attacks generated by spell effects cannot be deflected.

Whether the melee weapon you're wielding has reach or not, has no bearing on how it functions. If we parse this down, there's 4 conditions it looks for:

1. A ranged attack is being made against you, or an ally adjacent to you (your reach has no bearing on how far away you can protect someone, similarly having a reach weapon doesn't prevent you from protecting yourself or adjacent spaces). This ranged attack cannot be an unusually massive ranged weapon or be from a spell effect.
2. You're aware of the ranged attack. (I.E. If they're sniping you from stealth, you're not aware.)
3. You're wielding a weapon with which you count as having the weapon training class feature for.
4. You have an attack of opportunity to spend.

If you meet those four conditions, you can then spend an attack of opportunity to make an attack roll at full BAB with all of your usual bonuses and penalties. You do not get bonuses that would apply to AoO's such as Fencer since this is not an actual attack of opportunity, and penalties from things like usage of Power Attack on your turn apply. If the result is higher than the result of the ranged attack, it's deflected (see associated deflect FAQ).

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So to summarize into answers for your scenarios:

1. Yes.
2. Yes.
3. Yes.
4. Yes.
5. No, they're not adjacent.
6. No, they're not adjacent.