Fortnite added the ability for players to ride animals at the start of Chapter 3 Season 3, as an additional way for players to traverse the island.
At the moment, Fortnite players can ride boars and wolves as they're the only large animals on land in the game. There were rumors that Fortnite was adding Raptors as mounts, but so far that has not materialized.
Now, there's a new rumor that Epic Games will add flying mounts to Fortnite.
Reliable Fortnite leaker @HYPEX recently tweeted the information that Epic was working on adding "rideable flying animals" to the battle royale game.
According to @HYPEX, players who ride flying animals have the ability to "Boost and idle". Boost is presumably the flying equivalent of sprinting. Idle would likely mean that the mount can hover in mid-air so players can shoot or throw items more accurately.
The leak also mentioned the Saddler weapon, which was rumored to be added in Chapter 3 Season 3. The Saddler had a caption of "Aim, Fire, and Ride" and looks like it would attach to an animal. Fans have speculated that the Saddler could be used to hitch a ride on a flying animal.