Add the aquafaba, vinegar, mustard, honey and a generous pinch of salt to a high-powered blender or to a tall glass or jar if using an immersion blender. Blend on high speed until foamy, about 30 seconds.
With the blender running on high, begin to stream in the oil. Incorporate the oil very slowly, 1 to 2 minutes. (If using an immersion blender, raise and lower the blender near the end to incorporate air.) If mixture seems too thin, stream in more oil until the desired consistency is achieved. Use immediately or store in an airtight container in the fridge for up to 1 week.