The answer to 'why is my wasp trails' is that you likely have an active wasp nest near your home. Wasps leave chemical trails to mark their flight paths and the location of their nest, which can lead to visible 'trails' around your property. Common causes include a nearby nest in the eaves, attic, or other hidden location, or a food source that's attracting the wasps.
The symptoms of a wasp trail problem include seeing a consistent pattern of wasps flying along the same path, often between their nest and a food source. You may also notice the wasps hovering or landing in a specific area. Dealing with a wasp nest requires caution, as wasps can become aggressive if their nest is threatened.