We use low ESR capacitors in our drone to absorb voltage spikes, actually TVS diodes can achieve the same result sometimes even more effective.
Capacitors are like a buffer, they get charged up by current, and once they are fully charged they won’t work anymore. TVS diodes don’t have this limitation and they simply cut off voltage above certain value (based on your choice of TVS diode).
However TVS diodes don’t “smooth out” voltage ripples like capacitors do, hence doing nothing to noise. That’s the main reason capacitors are preferred if we had to choose between them. But you could use both of them if you want.
Here’s how to use TVS Diode in an FPV drone.
What TVS Diode to use? 22V is good for 4S, part number P6KE22A.
But is a TVS diode actually useful?
Jye Smith (the lead ExpressLRS developer) did some testing and found TVS diode has no benefits but adds extra weight to your drone: https://intofpv.com/t-tvs-protection-diodes-debunked
It won’t hurt to use TVS diodes on your drone, but they might not make as much a difference as some people thought they would.