What happens when a flying high creature is grappled? The rules for grappling state
you subject the target to the grappled condition
and the grappled condition is described as
- A grappled creature’s speed becomes 0, and it can’t benefit from any bonus to its speed.
- The condition ends if the grappler is incapacitated (see the condition).
- The condition also ends if an effect removes the grappled creature from the reach of the grappler or grappling effect, such as when a creature is hurled away by the thunderwave spell.
Keep in mind the grappler hasn’t moved, so it isn’t carrying the grapplee yet:
When you move, you can drag or carry the grapplee with you
The rules for flying declare the creature falls in this case
If a flying creature is knocked prone, has its speed reduced to 0, or is otherwise deprived of the ability to move, the creature falls
Basically the rules say:
- the grappled creature’s speed becomes zero
- the grappler isn’t carrying it yet
- the creature falls, because its speed is reduced to zero
- now it’s out the grappler’s reach and is no longer grappled
This sounds like a nonsense for me, so how exactly grappling works for flying targets?
For clarity let’s say the creature flies by non-magical means, using its own wings (a bird, an Aarakocra or something like that), and the grappler can be airborne using any means (magic, being carried by a flying mount, staying on a catwalk, et cetera).
Flying creatures are common in worlds of D&D, so the situation has to be quite trivial. The question is primarily about rules as written, not about adjudicating the situation using common sense.