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Bloons Wiki

This is a BIG plane.
~ In-game description

Flying Fortress is the final upgrade of Path 3 for the Monkey Ace in Bloons TD 6. It shoots 3 streams of darts and bombs, each of which fire +50% faster (from every 0.06s to 0.04s). The 3 streams of darts and bombs target the first, last, and closest bloons, respectively. Darts now deal 4 base damage instead of 2, and bombs now deal 5 base damage instead of 3, in addition to +2 Ceramic damage for both attacks. The Flying Fortress darts and bombs can pop any bloon type, including DDTs, although it needs camo detection (e.g. the Spy Plane upgrade) to detect Camo Bloons.

It costs $72,250 on Easy, $85,000 on Medium, $91,800 on Hard, and $102,000 on Impoppable.



The Flying Fortress is one of the largest flying towers in the game. It is a dark-gray twin-boom six-engine turboprop monoplane with two parallel vertical stabilizers at the end. It has three red turboprops and three respective white propellers on each wing, alongside a blue-and-red target symbol near the end of each wing (in-game model and Instamonkey icon only). The plane also has two rows of five windows at the front.

The upgrade icon for the Flying Fortress depicts a Flying Fortress plane flying directly forwards shooting a barrage of bombs and darts at the ground. Like Spectre, in its upgrade artwork the bombs are green with yellow stripes as opposed to the in-game Flying Fortress's dark grey with red on their nose.

Targeting Priorities[]

Like all Monkey Aces, Flying Fortress uses flight patterns as its targeting priority settings. It can also access Centered Path targeting option due to being an upgrade from the respective upgrade that grants it.

  • Circle: Flight pattern becomes a circular path around the runway.
  • Figure Infinite: Flight pattern becomes the shape of the infinite symbol (∞). As the Monkey Ace flies, it will pass its runway during its flight, specifically at each half of the whole flight path.
  • Figure Eight: Flight pattern becomes the shape of the number 8. As the Monkey Ace flies, it will pass its runway during its flight, specifically at each half of the whole flight path.
  • Centered Path: Flight path becomes a large circular path, centered around the center of the map by default. The center of the flight path can be changed manually. Can be accessed by purchasing the Centered Path upgrade, and once upgraded the Ace defaults to this target priority.
  • Wingmonkey: Instead of a fixed flight path, the Monkey Ace will attempt to fly as close to the path as possible, similarly to an Aircraft Carrier Plane. Available only via the Wingmonkey MK.
  • Reverse Flight: Shown by an icon of a reverse aircraft, the Ace will reverse direction of flight. Unlike other target priorities such as Change Hands, there is a cooldown of 5 seconds before being able to reverse flight direction again. It can be coupled with all flight options except Wingmonkey.

Flying Fortress's three alternating dart-and-bomb attacks are locked to First, Last, and Close, and the darts can home weakly at bloons.


Tower Prices[]

Updated as of Version 30.0
Total Crosspath Cost Easy Medium Hard Impoppable
Individual Upgrade $72,250 $85,000 $91,800 $102,000
0-0-5 $95,880 $112,800 $121,825 $135,360
1-0-5 $96,430 $113,450 $122,525 $136,140
2-0-5 $96,980 $114,100 $123,225 $136,920
0-1-5 $96,050 $113,000 $122,040 $135,600
0-2-5 $96,345 $113,350 $122,420 $136,020


At a very expensive price, Flying Fortress demolishes various types of bloon across any range in just a short amount of time, but its projectiles often miss fast bloons such as visible DDTs. Slowdown support such as Bloon Sabotage and/or MOAB Glue can help give the Flying Fortress an easier time handling DDTs. Extra support via Radar Scanner is highly recommended on top of Jungle Drums to improve its performance even further, especially with the 2-0-5 Flying Fortress crosspath.

Getting a buff from the Alchemist normally is not a good idea, as the buff wears off faster based on how fast the tower is attacking, but for this exact reason, Permanent Brew is an excellent choice for a good late-game tower combo. This is due to the fact that the alchemist buffs popping power per projectile and the flying fortress shoots a lot of projectiles very fast, every single one being affected by the buff. In fact, a super-buffed Flying Fortress outputs a huge DPS bonus outside of Sun Temples, True Sun God, and Paragons.

While Flying Fortress is impractical on CHIMPS, it still has its uses on CHIMPS. However, in the saveup for it, it needs to be affordable by the start of Round 95, given that the aforementioned round is nearly impossible with only a small amount of cash while also surviving subsequent and earlier late-game rounds. Most basic defenses with a very high potential for CHIMPS budgeting help afford Flying Fortress on time, particularly in combination with Sauda and MOAB Glue.


  • Like the Spectre, place the Flying Fortress near the exits. It should be attacking the front line of the bloons if the player does not have its path set to Centered Path.
  • It deals great damage against huge clusters of bloons, but it tends to fail against fast and/or spaced bloons, due to how slow each of the projectiles are. Therefore, it should not be used as the main popping power. Consider adding other towers to help counter this weakness of the Flying Fortress.
  • When upgrading the Flying Fortress along the other paths, it is best to upgrade to Path 1 (Rapid Fire and Lots More Darts) rather than Path 2 (Exploding Pineapple and Spy Plane), since by then Camo detection is easily accessible and an increase in its already massive attack speed and pierce is much more helpful. Also, the pierce and blast radius bonus from Exploding Pineapple crosspath for bombs does not do much because Flying Fortress already attacks so fast and deals such huge damage.
  • On most single-path tracks, it can solo through Round 90, making it a good choice to use in Impoppable mode if the player can afford it.
  • If facing DDTs, it is best to combine the Flying Fortress with a x/2/x Monkey Village to counter the DDTs.
  • Combining Flying Fortress with a maximized Ultraboost and Permanent Brew allows it to create complete doom for the bloons. Besides Sun Temples and True Sun God, Flying Fortress is by far a superior choice for utilizing attack speed bonuses.
  • Slowing down DDTs via Bloon Sabotage or MOAB Glue can help make Flying Fortress have an easier time hitting DDTs accurately.

Version History[]

Flying Fortress has been buffed significantly since it was first released. It formerly was much weaker than multiple Spectres while still constantly missing bloons, but has gained a series of attack speed buffs, damage buffs, and price buffs, alongside a general Spectre homing dart addition.

  • Change Indirectly buffed due to not being affected by the Spectre attack speed nerf. Flying Fortress attack speed remains 0.05s.
  • Buff Attack speed increased by +25% (0.05s → 0.04s)
  • Buff Dart damage increased (2 → 4)
  • Buff Bomb damage increased (3 → 5)
[...] Flying Fortress has also been reduced in price because, while achievable, it doesn't match well with freeplay progress.
~ Ninja Kiwi
  • Buff Flying Fortress cost decreased ($120,000 → $105,000)
[...] In addition to this we are experimenting with adding a small amount of homing to the spectre upgrade as rapid fire missing is not the intended design.
~ Ninja Kiwi, referring to seeking dart projectiles for Spectre
  • Buff Flying Fortress cost decreased ($105,000 → $100,000)
  • Buff Flying Fortress darts now have a very slight seeking effect on the dart projectiles.
Monkey Ace has had an overall rework to a lot of different upgrades in order to highlight the x1x Exploding Pineapples upgrade as a buff to all explosives, in addition to this Spectre has been reworked to have less base pierce but a higher damage bonus to Ceramic Bloons in order to make the new option of a pierce crosspath more viable while also allowing it to carry on better into the endgame against Super Ceramics.
~ Ninja Kiwi, referring to both Exploding Pineapple rework and Spectre rework
  • Buff Flying Fortress dart deals +2 damage to Ceramics, for 6 damage versus Ceramics instead of 4.
  • Nerf Flying Fortress dart pierce reduced from 30 -> 15
  • Buff Flying Fortress bomb deals +2 damage to Ceramics, for 7 damage versus Ceramics instead of 5.
  • Nerf Flying Fortress bomb pierce without Exploding Pineapples reduced from 60 -> 30
  • Nerf 0-1-4 Flying Fortress bomb pierce reduced from 60 -> 45
  • Buff 0-1-4 Flying Fortress bomb radius increased from 20 -> 23
More of a straight quality of life, Ace has gained a new special toggle button to allow it to turn back and fly in reverse on any selected flight pattern. [...] While Flying Fortress has started to see use in Boss events this feels like more of a cash dump than actual value in the tower. As Spectre value already drops off the later any game gets, the saveup into a ‘better version’ also drops off in value, and so the price should reflect that better.
~ Ninja Kiwi
  • Buff Flying Fortress price decreased from $100k -> $85k


Official artwork[]


  • Excluding Paragons, Flying Fortress is the sixth-most expensive upgrade alone, followed by The Anti-Bloon, Ultraboost, Super Mines, Legend of the Night, and True Sun God. This does not include the special variant of True Sun God, Vengeful True Sun God.
  • Like a multitude of other fast-shooting towers, this tower easily misses single fast-moving bloons despite excelling against much stronger bloons especially due to its awkward targeting.
  • Spectre bombs cannot pop DDTs, unlike the upgrade in Bloons Monkey City. The Flying Fortress can, however.
  • A 0-2-5 Flying Fortress will defeat a B.A.D. by itself on Logs and Cubism, but a 2/0/5 plus any Camo detection will be more effective.
  • Unlocking all upgrades along Monkey Ace's Path 3 towards Flying Fortress requires less XP than unlocking all upgrades along Ninja Monkey's Path 1 towards Grandmaster Ninja.
  • The Flying Fortress in-game has a blue-and-red target symbol on each side of the wing, but the official artwork does not. The Instamonkey icon for it does, however.
  • There are ten blue window panes on the front of the Flying Fortress. All ten of these can be seen in the front view of the Flying Fortress when seen in-game.
  • Some players refer to the Flying Fortress as "Big Plane", named after the Flying Fortress's official description, or as the "ISAB Plane", named so because of how ISAB's YouTube channel logo updated for BTD6 features a Flying Fortress.
    • Before ISAB updated his YouTube channel logo approximately starting from around when he uploaded his first Flying Fortress video, his old profile image was a Spectre from BTD5 Flash. Interestingly, the Spectre is the upgrade before Flying Fortress, which implied that ISAB wanted to "upgrade" his old channel logo for BTD6.

Balance changes[]

  • In Version 4.0, the Spectre was nerfed in attack speed, but the Flying Fortress remained unchanged, indirectly buffing this upgrade.
  • Before version 2.0, there was a bug such that there would only be 2 streams of darts and bombs if the Flying Fortress is placed under a village. This did not seem to affect its popping power though.
  • Despite countless price decreases, its price still always has a condition where its own upgrade price is more than $100,000. As of the 30.0 price decreases, Flying Fortress’s only condition for the aforementioned is its Impoppable price, at $102,000.

Community achievements[]

  • Various challenges have been done for Flying Fortress on CHIMPS Mode, starting off with attempting to afford Flying Fortress in CHIMPS Mode. Although it was surely affordable in CHIMPS Mode throughout all updates, it was not achieved until Version 18.0, with the release of Admiral Brickell.
    • Prior to Version 22.0 price buffs to the Flying Fortress, players had attempted to win CHIMPS Mode with a Flying Fortress; until Version 18.0 it was impossible, because a 0-0-4 Spectre plus a low-cost defense was unable to beat late-game on its own. There were only two maps where a Flying Fortress was affordable on CHIMPS until Version 22.0.
      • However, a Reddit post revealed that it is possible to beat CHIMPS while at the same time owning a purchased Flying Fortress, but only in Version 18.0 with Admiral Brickell and her old leveling curve, a 0-0-0 Dart Monkey, and a 2-4-0 Ground Zero. This was so far the only time it was done without money-related bugs.
      • The first completely non-bugged Flying Fortress on CHIMPS win was shown here and was shown on 27th July 2020. Again used Brickell, but this time without her XP leveling bug.
      • The Flying Fortress is possible to be purchased in CHIMPS Mode on Moon Landing as of Version 21.0, using 0-0-0 Alchemist, Etienne, and 2-3-0 Monkey Intelligence Bureau. This is possible because of buffs to Etienne on Version 21.0.[1]
        • This also marks the first time a Flying Fortress can be purchased before starting Round 100.
    • Flying Fortress is possible to afford on Downstream CHIMPS.[2]
    • The earliest round Flying Fortress can be afforded in CHIMPS is near the end of Round 94, using a combo of Captain Churchill, 3-0-0 Submerge and Support, 0-1-2 Ice, and 1-0-4 Spectre. One minor bug fix, which previously prevented Captain Churchill from dealing damage if both the shell and machine gun hit the same bloon, has helped reduce the total cost prior to Flying Fortress even further.[3]
  • The first 2TC combo for the Flying Fortress without use of bugs is 0-2-5 Prince of Darkness + 1-0-5 Flying Fortress, on Version 22.0.
  • Flying Fortress is currently the most expensive tower capable of achieving 2MPC, and this was first achieved in Version 23.0 but only barely affording it before starting Round 100.[4]
  • On Resort, a combo of Sauda, 3-0-0 Submerge Sub, 2-0-2 Monkey Village, and 0-2-3 MOAB Glue can solo till Flying Fortress on CHIMPS, provided that the Glue Gunner and Monkey Ace are both fully discounted.

Cultural references[]

  • The name of the Flying Fortress upgrade is based on the Boeing B-17 Flying Fortress, although the aircraft's appearance is based primarily on the Soviet experimental aircraft Kalinin K-7, an aircraft design which was made in the 1930s.
    • It's also likely a reference to the Spectre's original upgrade description in BTD5: "Flying fortress of bloon doom."