Jennifer Hudson is the biggest fan and critic of . . . Jennifer Hudson. The diva was spotted screening herself on a flight to New York this week after taping the “Christmas in Washington” show, where she performed for President Obama’s family. “She was sitting with her assistant and watching her own performance [on a laptop],” said a spy. “They both kept clapping, and Jennifer pumped her fist.” Hudson headlined the Dec. 11 concert with Justin Bieber.