The purpose of that paper was part of a thesis to outline a strategy for the use of a future weather modification system to achieve military objectives and it does not reflect current military policy, practice, or capability. The Air Force's policy is to observe and forecast the weather. The Air Force is focused on observing and forecasting the weather so the information can be used to support military operations. The Air Force is not conducting any weather modification experiments or programs and has no plans to do so in the future.
Contrails can form many shapes as they are dispersed by horizontal and vertical wind shear.
Sunlight refracted or reflected from contrails can produce vibrant and eye-catching colors and patterns. Observation and scientific analysis of contrails and their duration date back to at least 1953. Grid patterns of contrails in the sky are evidence of a systematic spraying operation. Contrails formed by aircraft may appear to form a grid as the winds disperse the contrails. More contrails are seen in recent years due to the growth in the civil aviation market.