Rapid Tracking "Weapons with this Special Rule are better able to utilize it for intercepting new arrivals on the Battlefield."
Each time a Model makes a Shooting Attack as part of the Intercept Advanced Reaction, it's Controlling Player can select a Weapon with this Special Rule for that Shooting Attack, even if it is not a Defensive Weapon.
Skyfire "Attacks made with the Skyfire Special Rule ignore penalties when attacking Flyers."
A Hit Test made for a Weapon with the Skyfire Special Rule ignores any Rule that would require attacks made targeting an enemy Unit that contains nay Models with the Flyer Sub-Type to be made as Snap Shots. Instead such an attack makes a normal Hit Test using the Ballistic Skill Characteristic of the attacking Model - this includes attacks made as part of any Reaction. A Unit that includes any Models with any Tactical Status may not benefit from the effects of this Special Rule.