This is a BIG plane.
~ Official description

Flying Fortress is the final upgrade of Path 3 for the Monkey Ace in BTD6. It shoots 3 streams of darts and bombs, each of which fire roughly twice as fast. The 3 streams of darts and bombs target the first, last, and closest bloons, respectively. Each dart and bomb also deals 4 damage and 5 damage per shot, respectively. The Flying Fortress darts and bombs can also pop DDTs if given Camo detection (with Spy Plane for example).

It costs $102,000 on Easy, $120,000 on Medium, $129,600 on Hard, $144,000 on Impoppable.


The Flying Fortress is one of the largest flying towers in the game. It is a light-black-colored monoplane with a long elevator plus its two tailwings at the end connected by two tail connectors. It has three red propeller holders and three respective white propellers on each wing, alongside a blue-and-red target symbol near the end of each wing (in-game tower and Instamonkey icon only). The plane also has got 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 highly damaging bombs and darts at the ground.


  • Like the Spectre, place the Flying Fortress near the exits. It should be attacking the front line of the bloons if you don't 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 the poor homing algorithm of the projectiles. 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.
  • 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 you're 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 maximizing attack speed bonuses.

Update HistoryEdit


Buff Attack speed increased by 20%


Buff Dart damage increased (2 --> 4)

Buff Bomb damage increased (3 --> 5)



  • 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.
  • 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."
  • Spectre bombs cannot pop DDTs, which is not like that in Bloons Monkey City. The Flying Fortress can, however.
  • 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.
  • Flying Fortress is the fifth-most expensive upgrade alone, next to Ultraboost, followed by Super Mines, Legend of the Night, and True Sun God. This does not include the special variant of True Sun God, Avatar of the Vengeful Monkey.
  • 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.
  • If playing on Easy mode and with the Aeronautic Subsidy MK purchased, the Flying Fortress will cost under $100,000 (at $91,800).
  • Players have attempted to win CHIMPS Mode with a Flying Fortress; although technically affordable on CHIMPS Mode alongside its previous upgrades combined, it is so far impossible due to how a Spectre plus additional low-cost defense cannot beat late-game on its own.
    • However, this Reddit link reveals 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.
  • 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.
  • 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.
  • 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. It can be seen here.
    • This also makes this the first time a Flying Fortress can be purchased before starting Round 100.
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