Three people, including two flight attendants, were taken to hospitals for treatment after the plane returned to Philadelphia, said spokesman McGlashen.
There were 265 people on board, including a crew of 10, when the Airbus A330 hit turbulence at about 17,000 feet over Delaware.
Flight 735 was flying from Philadelphia to Orlando at the time of the incident. There had been some reports of light turbulence in the area, but nothing as severe as what the plane ran into.
The Federal Aviation Administration will investigate.
In a separate incident, the wing of a WestJet737 clipped the horizontal stabilizer of aJetBlue plane while on the ground at Orlando International Airport. The horizontal stabilizer is the back set of wings.
The WestJet flight was pushing back from the gate when the incident happened, according to the FAA.
