Genshin Impact: Stamina stacking, does it work?
The answer is... no and yes.
No, it doesn't stack with other characters.
Yes, it stacks with food.
However, something more interesting was discovered...
00:00 - 02:06 1st Flight is fully stacked without food. That's having the bonus of Amber+Venti (20% each) and along with Wind Element Bonus +15%. This should give 55% less stamina consumption when gliding. Flight last 84 seconds.
03:34 - 06:03 2nd Flight is without Amber and the distance traveled is the same. Flight begin at 4:39 and also last 84 seconds.
07:32 - 09:33 3rd Flight is without Amber and without Wind Element bonus +15%. Flight begin at 7:53 and last 100 seconds.
11:00 - 12:52 4th Flight, I added Amber back in, but without Wind Element bonus. Flight begin at 11:12 and also lasted 100 seconds.
13:00 - Onwards... Didn't realize I didn't have the Glide stamina food ready, so had to go "cook" it. Yup, wasted 3 minutes of climbing, menu fiddling, teleporting, cooking, climbing again, etc.
16:50 - 19:31 5th Flight is with Food 25% reduce Stamina while gliding. Flight begin at 17:06 and last 145 seconds.
20:52 - 22:58 The final flight is with Wind Boost added back in while under Food effects. Flight begin at 21:04 and last 114 seconds.
So what I've discovered is that the Wind Boost is cutting short of our stamina. Instead of lasting 15% longer, it's lasting 21% shorter. In other words, it's the opposite effect. The description should probably read "Increase Stamina Consumption by 15%" instead of "Decreases Stamina Consumption by 15%" - We are moving faster, but our stamina is being depleted way quicker.