Aerith has somewhat of a mysterious presence in Final Fantasy 7 Remake, as many of the things she says hints that she knows more than she lets on. In Chapter 17, when the party is in the room she grew up in at the Shinra building, some of dialogue comes off rather puzzling, leaving more questions than answers.
[Warning: SPOILERS for Final Fantasy 7 Remake, Original FF7, & Final Fantasy VII: World Preview below]
"Follow them, the yellow flowers." Why is this significant? The intro of FF7 Remake opens with a dead flower. The next time yellow flowers are seen is when Aerith gives one to Cloud, who gives it to Tifa. The hopeful ending showing the flower petals fly from Marlene to Barrett contrasts the dead flower in the beginning scene. Multiple times throughout the game, they're said to represent reunion.
Reunion takes on multiple meanings: The reunion of friends, a more metaphysical aspect of long-time FF7 fans with a reimagined version of the game; and Hojo's Reunion Theory that Jenova cells will always find their way back to the source. Yet there's another reunion to the source: souls returning to the Lifestream. Aerith's painting in the Shinra building shows the Lifestream in a circle. This cyclic symbolism represents life, death, and rebirth, as seen with the flower, meteor, and phoenix (which has another yellow flower on its wing). As the flower has transformed multiple times throughout the game (dead in the beginning, alive between friends, and petals floating in the wind) it seems that following them is to follow the will of the planet.
Final Fantasy 7 Remake: "Follow Them. The Yellow Flowers" - A Message From The Planet
When Aerith says her enigmatic quote, her eyes become opaque, and she seems to trance out when speaking. It's like the planet is communicating through her, or at the very least, she is repeating something she's heard before. In Final Fantasy VII Remake: World Preview, an introduction to FF7 Remake, there is a short story by FF7 writer Kazushige Nojima about Aerith as a child in the Shirna building. Child Aerith starts drawing as if something has taken over her: a distorted face of a person, a tree, a flower, an animal, a monster - one on top of another until the paper turns completely black. Hojo comes in and asks Aerith if she sees anything, and she confirms that she can "see it...hear it." Hojo has her do more drawings in hopes she'll lead Shinra to the Promised Land, but Aerith says she "can't see it anymore." This seems to portray that the Lifestream or planet talks to Aerith when it wants, for a plan that she isn't entirely aware of. It also suggests that Aerith's mural is a message from the planet.
What this means for the story of Final Fantasy 7 Remake is still very much unclear, yet it hints at the planet's will and Aerith - who seems to be hiding something - may be little more than its puppet. It seems obvious the planet wants to stay alive, but it could also understand the importance of death and rebirth. The Shinra VR scene shows the planet in various stages: a thriving land under Cetra protection, a dying one when a meteor ends the Ancient civilization 2000 years ago, and a rebirth where Shinra builds Neo Midgar. From what is known from the original FF7, another meteor is expected to hit 2000 years after the first. The planet seems aware of this cycle and may even find it necessary, as life cannot happen without the spirit energy of the Lifestream, which is strengthened when souls return to it.
Aerith's drawings portraying life, destruction, nature, and monsters hint that good and bad make a balanced, essential whole, and this may mean that even Shinra, Sephiroth, and the party's questionable, destiny-altering actions at the end of the game could somehow be playing out as the planet intends. The developers still have quite a few mysteries for fans to unravel, but this understanding of the yellow flower representing the planet and its will, reunion, and a cyclic rebirth (which on a deeper level is another kind of reunion, as events of the game could bring about the reunion of a new world) allows for a novel experience in Final Fantasy 7 Remake while tying in to the original FF7, giving more depth and relevance to both titles.