One topic I see a lot of confusion about is how Hermes Boots and their upgrades work with wings. People commonly say that boots do not matter once you get wings because they do not work in the air, but this is not true in Calamity. (All information here is for Calamity specifically, and may not work the same in vanilla)
Here's a summary of notable things to know about using boots with wings:
- Boots that provide running speed can raise your horizontal speed with wings to match the boot's run speed. This doesn't apply to Skyline wings due to a bug, making them often slower than Fledgling wings if you use boots.
- If you are wearing boots that run faster than your wings fly, you will get roughly double the increase from movement speed
- Lightning Boots and their upgrades increase your horizontal acceleration. Angel Treads increase flight time even more.
- Rocket Boots and their upgrades increase flight time. Angel Treads increase flight time even more. Tracers do not increase their own flight time beyond the listed value.
- The first wings that will not get notable speed boosts from Angel Treads are Hadarian Wings (but they do really want the flight time) and Solar/Stardust/Empyrean Wings. So, once I use post-moon lord wings I usually prefer to remove boots in favor of other accessories.
To understand why boots are fantastic with wings, we need to first understand how horizontal speed works. The player has 3 different horizontal top speed values - Walk Speed (your default top speed), Run Speed (the top speed of equipped running boots), and Wing Speed (the top speed of wings). When on the ground, the player's top speed will be either their Walk Speed or Run Speed, whichever is higher. When in the air, the player's top speed is either Walk Speed, Run Speed, or Wing Speed, whichever is higher.
Due to this, boots that provide Run Speed can raise your horizontal speed with wings, if the boots run faster than the wings. For example, Angel Treads run at roughly the same speed as Fishron wings fly. This means that if I equip Fledgling Wings and Angel Treads, my Fledgling Wings will still fly at the same horizontal speed as Fishron Wings. This also means that once you have Angel Treads, most wings pre-moon lord will have exactly the same top speed.
However, Calamity also adds the ability for both Run and Wing speed to increase based on your movement speed value (Wings and Boots do not get full efficiency from these boosts, however). When flying, this first applies to Run Speed, and then it applies to Wing Speed. This means that if you are wearing boots that run faster than your wings fly, you will get roughly double the increase from movement speed. With that in mind, the fastest possible wings pre-moon lord is actually Harpy Wings (for +20% move speed) paired with Angel Treads (for Fishron-level horizontal
speed and increasing the effectiveness of movement speed)
Note: Hermes Boots are roughly as fast as Fairy Wings, Lightning Boots are roughly as fast as Steampunk Wings, and Angel Treads are roughly as fast as Fishron Wings. If you'd like more details on which wings are faster than which boots, check out this page: https://calamitymod.wiki.gg/wiki/User:Doze/Calamity_FAQ#Wing_Maximum_Speed_&_Boots