Denver International Airport is struggling to keep travelers happy while it undergoes a long and costly renovation in its main terminal, according to an annual study on airport satisfaction. J.D. Power surveyed more than 26,000 travelers from the United States and Canada for this year’s North American Airport Satisfaction Study. The Denver airport scored 777 on a 1,000-point scale in 2023, putting DIA in seventh place among twenty “mega airports,” or any airport with more than 33 million passengers a year…