How can I change AirPod volume with one hand? (while riding a bike)
You can pause the audio by modifying the settings of the AirPods so that when you double tap on an AirPod, instead of activating Siri, it plays/pauses instead. This can be done in Settings > Bluetooth > AirPods. As for volume, I don't think there's a way. I personally have my iPhone mounted to my bike (with a Quad Lock case), and I control the volume with the iPhone volume buttons.