Contrails aren't formed at low altitudes, only high..so if they were landing..what you were probably seeing is the accelerated air over the wing (since it's cooled when accelerated) condense (since as air cools, it can hold less water)....very common when the temp/dewpoint spread is right.

Contrails do not form over the wing tips at altitude, FYI,,they're produced by the engine exhaust heat interacting with the air.