Like many holiday travelers, “Gossip Girl” star Ed Westwick endured a long layover at the airport. He was trapped in Iceland for 48 hours waiting for a flight to London that was diverted, a source tells us. During the endless delay, “He walked into the duty-free shop and bought a bottle of vodka,” one spy said. “He looked like hell.” Also on the flight was Paul McCartney‘s girlfriend, Nancy Shevell. A rep for Westwick didn’t get back to us.