A very rare and massive contrail from a 787 has been captured on video. Boeing 747 pilot Christiaan van Heijst told Airlineratings.com that "the size of contrails normally depends on the humidity of the ambient air and the pressure difference over the wings. "The more saturated the air, the larger the contrail. The heavier the load on the wings is the larger the contrail. "Also, the type of engines can make a difference; the more fuel burned, the larger the amount of water vapor coming out the back." Christiaan is one of the world’s leading aviation photographers and his work can be found here. https://twitter.com/i/status/1362372542510473216