In this 1923 video, you can watch a plane dropping a curtain of titanium tetrachloride to hide ships, which is a yellow, non-flammable, and corrosive liquid which hydrolyzed when it comes into contact with damp air.

The resulting dense white smoke actually consists of droplets of hydrochloric acid and titanium oxychloride, which is pretty unpleasant to breathe in and requires goggles and a respirator to be worn when in close proximity with the smoke.