The first photo and the video show condensation shocks, when air is compressed close to Mach 1 and the compressible flow condenses the water vapor. From http://www.eng.vt.edu/fluids/msc/gallery and http://seb.ouvaton.org/.

The second photo shows the condensation forming above a wing during takeoff as a result of the low pressure forming above the wing on a humid day. The low pressure and low temperature during high lift cases (high-g or takeoff) would cause water vapor to condense. From http://www.jetphotos.net/.

Contributed by Phillip Kang, Princeton University.