In 1.11 they added rocket propulsion elytra flights (aka using fireworks when flying with an elytra). This is pretty awesome.
For comparison, here are various forms of transit for the Aahrus to Spawntown ~400 block route.
Rail Route 5: 1:44
Horse with speed II: 0:51
Nether ice road with ender pearl elevator: 0:28
Elytra flight with sporadic boosting (2 flight dur 1 boosts): 0:31
Elytra flight with consistent boosting (6 flight dur 1 boosts): 0:19
Another example, Aahrus to the eastern swamp peninsula of my regions ~1400 block route.
Nether route: 0:36
Elytra flight with sporadic boosting (4 flight dur 1 boosts): 1:17
Elytra flight with consistent boosting (10 flight dur 2 boosts): 0:44
Fireworks and elytras aren't a super renewable resource though so I imagine its use isn't good enough to replace the nether. To get really good times out of it you're committing probably 10 gunpowder and 10 paper (10 fireworks with no charge and flight duration of 1) per 1k blocks traveled. Still pretty good and a not so bad option going somewhere with inadequate nether infrastructure.