Accurate

@Liggliluff  
Thus my comments about catching air and parachutes.

@Cirrus Light  
If you were free falling in vacuum, then your clothes would stay put. But free fall in the open will cause air resistance, and clothes usually are affected more by air resistance and have a low terminal velocity.
 
Free fall in a enclosed room, like the aeroplane, there’s no winds as the air is forced down with you, just like if you were sitting in a car with the windows closed.

@Liggliluff  
I think that’s the main thing. And keep in mind even free-fall towers don’t accelerate down, they just drop freely, at most. And the seat is still there and you’re secured down into it, so the dress can’t flare up any higher than the seat goes down the legs, at least.
 
And that’s assuming it catches enough air to make it flare. You have to pack parachutes very carefully to make sure they do that.
 
If you really want a bad place for a dress, try microgravity :p
 
But apparently that, even, isn’t too bad.
 

 
Might be because they’re on short little micro-g flights on the vomit comet, though - an aircraft that flies parabolic free-fall trajectories to make everything inside weightless for 30 seconds at at time or so. Maybe it’d be worse if gravity weren’t keeping her dress down every 30 seconds, or maybe they did something in particular with her dress to keep it from flaring up.
 
All I know is I’m jelly of that guy, lol.

@Liggliluff  
That’s truth.

@Sweet Blast  
Then my understandings of this was wrong. Maybe the dress is kept in place thanks to the seat and all safety stuff. So even in a free-fall attraction, the dress will still stay put.
 
Well then, wearing dresses to amusement parks isn’t so bad after all.

This image is terrifying.
 
Cute idea though.

@Liggliluff  
@Sweet Blast  
It may feel like you get negative g’s, but I don’t think any rollercoasters actually do that. It’s just lower g from plummeting downward feels negative.
 
As for wind, since it always moves along the rails, it’ll always be running into air forwards.
 
So no Marylin Monroe moments, great as they may be.

@Liggliluff  
I were in dress on rollercoaster. Nothing happend what you mentioned 😅i

Somehow dress + rollercoaster doesn’t seem like a great idea. I’m imagining high speeds with strong winds, and she’ll end up with a skirt in her face, and her panties quite visible.

For a second I thought it was some body-snatcher horror moment of - “So uh… why is there two of each of us on this image?”

Human Dash and Pony Flutters look horrifying.