http://findarticles.com/p/articles/mi_hb3101/is_2_54/ai_n29351723/?tag=content;col1

this is a great article on early thoughts about contrails – trying to figure out what they were exactly, with various explainations over the years.

It covers the Argonne case mentioned above, and how people tried to explain what the contrails were over the years.

There are references to contrails immediately after WW1 being 40 or 50km long, to contrails at ground level from motorcycles. It proceeds through discussion of the practicalities of air combat as seen in the 1920′s and 30′s, early high altitude flights, increasing altitude capabilities of aircraft – P-26′s starting to operate up to 30,000 feet, the Spanish Civil War where 109′s and I-16′s played a game of “who can fly higher and so get the advantage” with each other (109′s had the early advantage until the I-16 type 10 came along) and perhaps the 1st ever eye witness account of combat contrails, in 1938.

There are extensive end notes too.

http://contrailscience.com/chemtrail-myths/#comment-5185

We are seeing HUGE contrails forming at levels as low as 25-30%. Can you explain this via the “normal” explanation?