Flamenco dancers use the words bata de cola to refer to both a dress and the dance it's worn for.
The bata de cola is a dress with a long train - if it's white, it can look rather like a ruffled wedding dress! At first glance it looks like a "feria" dress - the dresses worn for the Seville fair, which are too tight around the legs to dance properly in. However if you look closely, you'll see the ruffles start above knee level, giving enough room for the legs to move. And you need to move your legs a lot in this dance, not just to do the steps but to move the train around!
A well-made dress will have a train with enough stiffness to stay spread out at all times. A soft train may look easier to handle but it's actually more difficult - and it also looks less impressive. Look closely at this clip and you'll see the choreography is restricted to allow for the fact that the train won't fly properly:
Now compare with this clip: