One thing that needs to be determined is what the normal air traffic routes are in a given area. It becomes suspicious when air traffic is extremely heavy in a particular section or sections of the sky, until that area is basically covered with contrails and then the planes either stop flying in that area or the contrails stop lingering and spreading when subsequent jets fly through. This morning I did see one jet go by in the same area and altitude and it did not form an expanding contrail. Contrails are suppose to disappear like the wake behind a boat. On days where the atmosphere is more humid the contrails may linger a bit longer but they are not supposed to expand to cover the sky. Many baby boomers know for a fact that everyday contrails never expanded to form cloud cover...until around the 1990s
The explanation below talks about the formation of contrails being similar to our breath forming clouds of moisture in the air on a cold day. Well......our breath never does form a cloud that lingers or that expands. Once the heat from our breath dissipates, the condensation disappears. I believe it is similar when the heat expelled by the jet engines cools off...the contrail should disappear.
The following link gives this explanation for the formation of contrails
How do contrails form?
For more info and photos on contrails/chemtrails see http://lymesentinel.blogspot.com/search/label/CHEMTRAILS