Two more pictures of contrails taken many years ago. Are contained in a study of 1972 ; complete reference: RG Knollenberg, "Measurement of the growth of the ice budget in a persisting contrail," Journal of the Atmospheric Sciences, vol. 29, 1972 .
Note that the second shot to the concept of "persistent trail, often flaunted as a symptom of something strange ; actually 'a thing normally seen in any scientific study - so it' s true that many studies that, starting from the consideration that many long contrails remain in heaven, evolving into cirrus clouds, we deal with the impact on climate due to a possible increase in cloudiness' because of the contrail.
