United Airlines showed off the carrier’s first Boeing Co. 787 jet at a media event Thursday in Everett. The airline will be the first North American carrier to operate a Dreamliner. Boeing is expected to deliver United’s 787 in September. The 787 rolled out of the paint hangar on Tuesday, sporting a gold line that swoops from the aircraft’s nose to its tail. Boeing uses the swoop design as part of its paint logo. United used the swoop on its 787 in tribute to the airline’s longstanding relationship with Boeing.