"The human body houses a fragile, round soul. What those humans live on is a huge, round orb below. And, what the superior people live on... Is that lunatic orb behind me."
— Kaguya Houraisan (Imperishable Night Stage 6)

The 089-HK (Codename: Kaguya) is a single engine, single seater, super high speed, extreme maneuverability fighter. This jet is a mix between an F-86 Sabre and an A6M2 Zero. This jet was based on the bamboo princess of Touhou Project, Houraisan Kaguya. Character's wiki:

Kaguya Houraisan is the main antagonist of Imperishable Night. She was once a princess of the Lunarians, a race of people living on the Moon. For the crime of creating the Hourai Elixir, she and Eirin Yagokoro were exiled to the Earth, where they came to live in what would eventually become Gensokyo. She is currently the princess of Eientei.

Kaguya first appeared as the true final boss in Imperishable Night, then appeared as a stage 9 target in Shoot the Bullet. She made a brief cameo in the backstory of Legacy of Lunatic Kingdom.

Personality
Kaguya has a rather carefree personality, as she often sneaks out to visit the human village. She apparently is refined in the art of conversation, but her spoken language is a bit dated. She is also described as haughty and relatively wild.

Abilities
Manipulating eternity and the instantaneous
Eternity is namely immutability, and it can be said that eternity rejects all change. Things that possess eternity indefinitely don't change, and also cannot be interfered by things outside of it. By using her ability on everything in Eientei, she made it so that living things stopped aging, objects would never break, and food would never spoil.[5] Additionally, beginning from when Kaguya came to Gensokyo, she has lived hidden away for hundreds of years, but until the Eternal Night incident, she continued having an existence in the interior of the Bamboo Forest of the Lost without anybody knowing about her. Also, the pure Japanese-style building Eientei can be seen not to have worn out at all, which can be said to have been due to this ability of eternity. After the Eternal Night incident, Kaguya removed the spell of eternity from Eientei, causing objects to break as normal, living things to age again, and food to spoil if not eaten in time.

Incidentally, as the Hourai Elixir made by Kaguya's ability of eternity is something that makes the consumer have a "body that rejects all change", it can simply be said to be a kind of maximised, self-healing ability (due to this, it's said that a the whole-body can recover from a single hair, as for Fujiwara no Mokou). In the last spell card "End of Imperishable Night" which used this ability, it destroyed Reimu Hakurei and the others' spell of eternity, and forcibly called for dawn (End of Imperishable Night -Rising World-, where "Rising World" was a homophone to "dawn" as "yoake".

With "instantaneous", it's namely the gaps, the instant that's impossible to recognise the existence of anything else. Kaguya, in being able to manipulate the instantaneous, is able to alter the needed "instants" and make them her own time. However, whatever she gathers together, since the fact that they're the "unrecognisable instant" can't be changed, she has no means of knowing what's within the instant. For this reason, in manipulating the instantaneous, Kaguya's able to spend "time the same as others'" and "time different from others'" simultaneously. Hieda no Akyuu presented this as "having parallel timelines at the same time." In the nineteenth chapter of Silent Sinner in Blue, as the instantaneous is the smallest unit of time, time is able to accumulate countless instants. Watatsuki no Toyohime explained that to see time as continuous is due to the inability to recognise the instant.

Since her ability can be said to be the ability to manipulate "complete stop = eternity" and "extreme speed-up = instant", Akyuu also summarised it as an "ability to manipulate time". This seems very similar to Sakuya Izayoi's "ability to manipulate time".

Jet's informations:

Maneuverability:
-Roll half a circle in a blink of an eye
-Pitch 180 degrees in just 3 seconds
-Top speed is 1939 KMPH

Weapons:
-14x danmaku guns

VTOL down for flaps, trim for trim.

Have fun!