Because the passengers are asleep when Agent D enters the cabin, the plane must have been en route for about 8+ hours already when the map starts. Therefore the map doesn't start with Agent D boarding the plane, but rather with her emerging from a lower deck, where the plane's staff resides. It is unknown how long she needed to be in disguise before the events of Toxic (2023) play out.

Agent D walks through the plane's 4 economy sections and acts as a steward: waking up passengers, serving them and ensuring they are safe when they dance.

From the last economy section it can be assumed that the planes in the Just Dance universe allow (and possibly encourage) their passengers to dance while safely airborne. It could be possible their flow is what fuels the plane most of the time, reducing the need for fossil fuel and allowing the planes to have practically no emmisions.

As she reaches the end of the economy section Agent D encounters and successfully fights off two hi-jackers, members of an unknown organisation and disguises herself as a V.I.P. upon reaching the luxury section to blend in.

The first class cabin section of the plane can be assumend to be as long as the 4 economy sections combined. It is at least significantly larger than one of the economy sections.

Upon exiting the luxury cabin, she encounters two more members of the hijackers and successfully fights them off.

The disguise Agent D uses in the V.I.P. section has no officially confirmed alias attached to it as of yet. We can assume that it is a secret Identity that Agent D has taken on numerous times before, as none of the other V.I.P.'s question her presence - meaning it would not have been odd for this Identity to be on board with the other V.I.P.'s My guess would be it is the Secretary from Womanizer (Just Dance 1) - this would imply that the other V.I.P.s might be several other high ranking members of the same Company that the Secretary works for. Whether there is a real person that she is impersonating or if this Identity is 100% fake is unclear. I would argue, that the latter is the case.

Finally Agent D changes out of her disguise into her regular spy gear to traverse the luggage hold. At this point it would seem that the Hijackers are trying to keep her from advancing further by letting the plane fly erratically causing the luggage to fly around.

As to why the planes cargo is not secured, this might also be the work of the Hijackers

The next section which features security lasers could be argued to not be part of the plane - but rather Agent D remembering her training or a different mission, using this skill to dodge the flying luggage. (I certainly have never heard of security lazers like that on a regular passenger plane.)

Agent D fights off the remaining pair of Hijackers. She hen reaches the cockpit and frees the plane's pilot Captain Catastropha from his ropes, revealing that her aim was to stop the hijacking of the plane. She then takes the helm herself and flies the plane.

I would hazard to guess that Agent D not letting Catastropha back on the helm after freeing him, implies that she won't fly the plane to its intended destination either, but rather to her base or HQ as the plane is seen later in Gimme More, meaning she kept it after the mission. She basically hijacked the plane from the hijackers.

Remaining Questions

What's the aim of the hijackers?

Seeing as there was a V.I.P. section to the plane maybe the enemy organisation wanted to kidnap the influental people on the plane. They infiltrated the plane before it took off and as it was far away from the airport they took control off the plane by tying up the pilot and steering the plane off-course to their base. The pilot, regular passengers and other staff on the plane would become additional hostages.

What was Agent D's Mission?

"Operation SKY" was about stopping the hijacking, retrieving the hostages and securing the plane. Upon regaining control of the plane, Agent D was further tasked to fly it to her base instead so all the people on board could be asessed and taken in as witnesses. That way any organisation memebers that were still in disguise and weren't thrown out of the plane by Agent D could be caught.

Where is the Co-Pilot?

Notably there is only Captain Catastropha in the cockpit when Agent D arrives. Despite there being 2 seats, there is no co-pilot. I would say that Captain Catastropha's co-pilot was one of the hijackers. When the hijackers enitiated their take-over the co-pilot with the help of a collegue overpowered and restrained Catastropha in the co-pilot's chair, then took over the steering. These two are the ones Agent D fights before reaching the cockpit. When they couldn't stop her with the luggage hold manouver they went to confront her directly (and lost).

What is the Extreme Version?

Toxic - Extreme (JD 2023) is most likely a training that Agent D had to undergo in order to become a spy/ to stay in form. She remembers this training when she has to navigate through the luggage hold of the plane in the Classic Version and it helps her succeed. Though the map could also be a glipmse at another mission where she had to traverse actual security lasers. this is not confirmed as of yet. It utilizes the same costume seen in the later sections of the Classic Version and confirms that this is her true appearence. It also serves as an extended version of the section with lazers in the classic map which was inspired by the Toxic Music Video.

Further Points of Note:

Plane Layout Visualized:

The plane shown in Toxic (JD 2023) is different from the one seen in Dragostea Din Tei (JD 2017), the map Captain Catastropha originates from. The Toxic plane is fully pink, while the DDT plane is white with blue accents and the text "Just Dance Air". As of yet it's unconfirmed weather the pink jet from Toxic belongs to the "Just Dance Air" airline, but it can be inferred from Captain Catastropha being strongly implied to have been the pilot of the plane.

Captain Catastropha bears resemblence to P2 of Mana Mahna (JD 2015) He and either one of the other Mahna Mahna coaches or P2 of Hey Mama (JD 2016) could be the parents of Catastropha.

The flight attendents in Mahna Mahna (P1 & P2) have a significantly different uniform from the one shown in Toxic. Notably the uniforms in Mahna Mahna are pink, while the Uniforms in Toxic are blue. It is the inverse of the planes' color difference between DDT and Toxic. This could either mean that Mahna Mahna is a different airline or that the airline changed the designs of their uniforms at some point.

During Toxic the main color of Agent D's appearence goes from blue to purple to red. The purple costume being a sort of transition state between the fully disguised Agent D and the undisguised Agent D. Seeing, how the purple costume bears resemblence to the mainly blue coach of Womanizer (JD1) this might imply that Agent D is taking on the appearence of a younger self where she was working as a secretary, and might be the reason for her hairstyle change to a bob cut in Gimme More.

The plane seen at the end of Toxic shows up during As It Was (JD 2023), the noise of it flyng over being used as a censor. The time placement of this cameo is unclear but it does tie Hadley to the Agent D Saga. It is most likely that this cameo takes place right after the events of Toxic, i.e. when Agent D is flying the plane to her base. Because the plane is flying very close to the ground it implies Hadley lives close to Agent D's base and might even be a fellow agent. Another possibility would be that the cameo takes place after the events of Gimme More - i.e. after the plane launches from Agent D's Base, which carries the same implications for Hadley.

Due to "Operation SKY" being confirmed to take place in Sun Horizon, unless planes can be used to travel between Danceverses, this would put As it Was and by extention Agent D's Base in Sun Horizon aswell.

This is it for now. Thank you for reading.