Thermals

As an alternative method of getting higher when flying with elytra, there should be thermals above "hot" blocks (i.e. magma, lava, sand in the desert biome) that slowly lifts the player if they fly above it. The amount of lift given to the player would depend on the type of hot block and, in the case of desert sand, the time of day (it's not hot at night). This could be interesting if the player is flying at low altitudes and hits a thermal, or purposefully placed by a base to save expenses on fireworks, as mentioned before.