Approaching Dublin Airport, Ireland with a an atmosphere filled with moisture this Emirates Boeing 777 is showing how the air behind is being disturbed as he passes through it. Also as the air above the wings is travelling much faster than the air underneath the wings and this is extenuated because of the flaps being deployed for landing, the moisture laden air is then being condensed and this causes the vapour above the wings. You will notice that this is only were the flaps are extended. As an added note the ribbon like trails are coming off the end of the flaps and turn in opposite directions to each other. It shows that if another aircraft is travelling close behind, you can expect the approach to be rather bumpy. This is why air traffic control separation behind heavy jets is so important. There has been incidents where smaller aircraft have been downed by wake turbulence.