Latias and Latios presented some very unique powers in the movie, such as sight-sharing, invisibility and shapeshifting. They are also very fast and cover wide ranges in terms of orbits, and rather patient and tenacious. Other than that, this Latias and her brother mainly tackle to fend off enemies, or to emit powerful, protective fields of light that can be enhanced even further in cooperation when they are forced to do so. However, in contrast to her brother's attitude, Latias is rather afraid of fighting with larger enemies, and tend to take a distance from foes (dislikes of conflicts and battles are common among the sibling). However, based on her behaviors seen in the movie, she could have get used to the urgent situation as the time passed.
Latias commonly shapeshifts to appear the same as Bianca, and befriended Ash under her persona. She may have a crush on him as well, as was hinted in the movie, undoubtedly because he saved her from Annie and Oakley.
+ indicates this Pokémon used this move recently.* - indicates this Pokémon normally can't use this move.
She is seen very curious, kind and elusive in nature like those of cetaceans (dolphins and whales) and pinnipeds (seals and sea lions).
The sight-sharing is called Yume-Utsushi (夢映し; Dream-casting) in Japanese.
The technique which is to emit filed of protective lights used for both offence and defense, used by Latias and Latios in this movie was almost identical in visual effect with Luster Purge in game versions.
This Latias and Latios are some of few Pokémon featured in the movies that haven't demonstrated any ranged attacks with projectiles. They are also only legendary Pokémon of dragon type that weren't been involved in battles assertively.
In the movie-related comic version, Latias succeeded to defeat the Aerodactyl herself after overcoming her fear by tackling the opponent strongly with holding Ash and Pikachu in her arms as a surprise attack which her brother is good at thanks to their unique abilities.
Latias seems to camouflage herself in illusion of Bianca rather than actually transforming.
Latias, even when she camouflage her in human form, can be distinguished from other humans by difference in body temperatures.
Ash was strongly believing that it was Bianca who came to see him off when he leaves Altomare. This was possibly because he had presumably finished his farewell with Latias beforehand. This Latias's ultimate fate is unknown.
The title of the background music during the kiss scene is Canon, same as Bianca's name in Japanese.
Latias and Latios continue to be worshiped as a guardian deity of the city even today, and are popular from citizens of Alto Mare, equivalent to the winged lion in Venice.
With Latios and Pikachu
About to demonstrate the sight-sharing
Latias attempting to save Latios from the DMA
Determining the readiness to save the city and preciouses
Latias and Latios rushing to ward off the tidal wave (in the trailer version)
Connecting with her now deceased brother
Latias as Bianca or real Bianca kissing Ash
A picture showing possible ancestors of the sibling saving Alto Mare