Every Thanksgiving, airports across the country are jammed with travelers impatient to enjoy a brief holiday weekend away from home. In addition to the usual bustle, air passengers this year will also contend with extra construction at the Minneapolis -St. Paul International airport. Construction crews are working around the clock on a massive airport upgrade. They're erecting more parking ramps, more gates and a skyway to connect far-flung areas of the airport. They are also building an underground train that will move passengers quickly between concourses. Overseeing the project is Denny Probst, director of Land Side development at the airport. He says the improvements should help the airport keep pace with the growing number of air travelers.