The 1,000-foot display of lights outside Denver International Airport is experiencing technical difficulties. Intended as a showpiece for the airport’s ambition and Panasonic’s LED technology, the $14.5 million government-funded sign has produced one headache after another for the city airport. Now, it has gone mostly dark. The display, consisting of hundreds of illuminated rods and several television-style advertising displays along Peña Boulevard, was powered up late in 2017.