I actually saw this condensation cloud form briefly on a Blue Angels F/A 18 during the San Francisco Fleet Week air show last month. One of the jets was coming in over the Golden Gate bridge and the cloud formed -- and was gone in a half second or less. I had no idea the jets were that close to transonic speeds. It was incredible to see.
Did vapor cloud on the Blue Angels' F-18 look like these photos:
1. http://ChamorroBible.org/gpw/gpw-20050914.htm -- Via http://ChamorroBible.org/gpw/gpw-The-Spectacular-Clouds-of-the-Transonic-Flight-Regime.htm
2. http://www.AirShowAction.com/picweek.html -- Via http://www.AirShowAction.com/flw98/flw98.html
3. http://www.GalleryOfFluidMechanics.com/conden/flw2.htm -- Via http://www.GalleryOfFluidMechanics.com/conden/pg_sing.htm
4. http://www.GalleryOfFluidMechanics.com/conden/am1376.htm -- Via http://www.GalleryOfFluidMechanics.com/conden/pg_sing.htm