AirStrike 3D II makes many improvements over the first installment, such as adding a story, named characters, and unlockable helicopters that have different stats.
Unused Level#
Inside the game's pak1.apk archive is a level not listed in the game and the only one without an entry in levels.txt which is located in the same archive, its filename being level_konion.hsc, this potentially being a misspelling of "canyon". Given that it has no enemies, powerups, buildings, or endpoints, it was most likely used as a test level or a template.
Since it doesn't have a level entry, it's unknown which texture bank it's supposed to use, although none of the existing ones look out of place when loaded on this level.