On Game of Thrones, Bran's psychic powers grew tremendously after his time training with the Three-Eyed Raven. He can access visions of the past and present, as well as warg into other humans and animals, which means he can see through their eyes. He did so with both his direwolf Summer and with Hodor. Some fans have wondered just how far those abilities can go and how they might help Bran during the big upcoming battle against the encroaching White Walkers. It may sound implausible at first, but bear with me: will Bran warg into a dragon on Game of Thrones? There's a very popular theory from the books that might suggest it.
In George R. R. Martin's The Song of Ice and Fire series, Daenerys sees a vision in which she's told that "the dragon has three heads," which some believe refers to three people who will someday ride Dany's three dragons. She would obviously be one of them, but fans, like reddit user svenhoek86, have speculated that Bran could either be another rider or warg into one of the dragons. But why Bran specifically, especially when the series has such a wide cast of characters?
It's a line from the Three-Eyed Raven that puts Bran into consideration. Bran was told that though he would never walk again, he would fly, which definitely makes it sound like he could be warging into a dragon some day.
If Bran is able to warg into a dragon, it could also explain why the Night King wants to do away with Bran specifically: he is a threat because he could use those powers to control the dragons and help bring about the Night King's downfall. If the Night King knows the future (and what undead zombie ruler doesn't?) then he could want Bran gone so there's one less person out there who could possibly destroy him.
But there's some debate about whether Bran will warg into the dragon or actually ride it. As reddit user talestosco has pointed out, Bran was told that he would never walk again, but he was able to walk again by warging into Hodor and Summer, so perhaps warg activity doesn't count. If that's the case, then Bran could fly by saddling up a dragon. Or by inventing a plane da Vinci-style, which would be cool but kind of anticlimactic.
Bran's abilities are too significant not to have a major payoff down the road, and his involvement with the White Walkers (like seeing them in visions and being touched by the Night King) seems to indicate that his abilities will come into play in the eventual confrontation. And what better way to battle ice than with fire? If Bran could control a dragon, then he could be incredibly useful in the fight to come.