(SeaTac, WA)  --  Officials at Sea-Tac International Airport say an American Airlines plane was forced to return to the airport after hitting a bird.  The impact left a dent yesterday afternoon in the nose of the Dallas-bound Airbus A321, measuring two feet across.  The plane landed at Sea-Tac after staying up for a while to burn fuel.  The 150 passengers later boarded another plane to finish their flight.