"I was aboard this aircraft. The take off was fast, rather quick and felt short. Then we pitched down and banked right (left wing up) and then left (right wing up) and the back felt to skid out sideways, I was in the window seat just behind the left wing. Then it felt like the pilot pulled the aircraft up manually. He continued to make very strong left and right banks while in the air before we circled back to JFK.
Sounds like a wake encounter.