A new targeting option enables Heli to seek and pursue the Bloons automatically.
~ In-game description
Pursuit is the second upgrade on the first path for the Heli Pilot in BTD6. It gives the Heli Pilot a new target priority: Pursuit. Pursuit target priority allows the Heli Pilot to follow bloons that are the closest to the exit, equivalent to the target "first". This is automatic, no touch is needed. Setting a Heli Pilot to Pursuit can be very useful for allowing the player to focus on other towers instead.
In BTD6, the Heli Pilot automatically changes to Pursuit Mode upon purchase of the upgrade. Unlike in BTD5, the Pursuit targeting has improved so that it will follow along the track as close as possible to the front of the bloon, compacting with other Heli Pilots on Pursuit in the order of whichever Heli Pilot went to Pursuit first.
Pursuit is primarily designed as a hands-free upgrade for letting the Heli Pilot automatically target bloons, which in turn may allow for less micromanagement of the Heli Pilot. In terms of practicality, it is mostly used strategically for defenses that include Banana Farms, as picking up bananas is often disturbed by manual micromanagement of the Heli Pilot.
Unless hands-free defense is necessary for a special purpose, try to avoid purchasing this upgrade, as normal Heli Pilot micromanagement is usually offers more efficient control over the Heli Pilot.
It is not recommended to use Pursuit targeting in combination with the Razor Rotors upgrade, as a Razor Rotors on Pursuit targeting tends to underperform versus Lead Bloons, even with the slight rotor range buff.
The Pursuit upgrade can be used in combination with Downdraft to effectively blow back the Ceramics spawned from early MOABs directly after destroying them.
Pursuit Helis will stop moving wherever they are as the round ends. This can end up in them wasting time flying back into range when the next round starts, especially if not equipped with Bigger Jets. This can be remediated by turning off Auto-Start, switching to Follow Touch (Follow Mouse on desktop versions) and placing them at the entrance manually.
Pursuit received insignificant changes since it was first released in BTD6. However, the Pursuit targeting option is now modified, its previous upgrade is now more expensive, and the Heli Pilot's base cost was slightly increased in later updates.
Pursuit targeting now changed to follow a few units in front of the bloon rather than simply a certain number of units away from the bloon at any angle.
Purchasing the Pursuit upgrade now automatically sets Heli Pilot on the Pursuit target priority.
Instamonkey Heli Pilots with this upgrade or above now automatically are set on Pursuit.
Heli Pilot manages on pursuit far too easily without any need to consider Bigger Jets unless camo or downdraft is required. For more crosspath variety than just 'camo' we moved more of the base Heli speed out and back into Bigger Jets with an overall buff to Bigger Jets. This should allow Bigger Jets to scale a little better than other helis through early speed ramping. [...]
~ Ninja Kiwi, referring to base Heli flight speed versus Bigger Jets
Affected by base Heli flight speed nerf versus Bigger Jets crosspathing
Crosspathing in BTD6 (Top: Path 2, Bottom: Path 3)
Pursuit is the only BTD6 Heli Pilot upgrade that costs less than its preceding upgrade.