1) "Chemtrails" are just normal condensation trails.

2) The so-called chemtrail haze is just virga.

3) Criss-cross patterns, asterisks, As, Vs, Xs in the sky form because planes follow radio beacons.

4) Contrail persistence is a function of air relative humidity.

5) On/off trails occur because the plane flies through pockets of dryer air.

6) There is the storage problem addressed in the "Problem for the chemtrail believers" thread.

7) Aluminum oxide emission is caused by SRMs.

8) Barium compounds emission is caused by mining and refining industrial processes.