Fighter Plane is the third upgrade in Path 1 for the Monkey Ace in BTD6. Alongside allowing the Monkey Ace to fly at a faster velocity, it shoots 2 powerful seeking missiles at M.O.A.B. Class Bloons, inflicting 25 damage each. It costs $850 on Easy, $1,000 on Medium, $1,080 on Hard, and $1,200 on Impoppable.
Fighter Plane is a good tower to use against breaking open the layers of early MOABs.
There are huge advantages compared to the MOAB Mauler. Fighter Plane is able to shoot seeking anti-MOAB missiles at any distance without Line of Sight problems, despite not being very good against grouped MOAB-class and being only a few hundred dollars more expensive.
One Fighter Plane is almost always able to break open the outer Fortified MOAB layer of the Round 40 Fortified MOAB in Alternate Bloons Rounds, though it needs additional assistance to pop the Fortified Ceramic children efficiently since it cannot defeat the Fortified Ceramics by itself.