Columbus Municipal Airport (CLU) in Indiana does not have a lounge, which fits its role as a general-aviation field rather than a scheduled commercial passenger hub built for that kind of amenity.
Columbus, Indiana is a genuinely distinctive small city, known nationally for its concentration of modernist architecture, a reputation that has earned it comparisons as a design destination well beyond its size, and for Exhibit Columbus, a recurring architecture and design exhibition held in the city. Columbus is also home to Cummins Inc., the engine manufacturer headquartered there, whose corporate flight operations are among the airfield's principal users. None of that changes the airport's basic character: it serves general aviation and corporate traffic, not scheduled airline passengers, and the terminal building reflects that smaller, working-airfield role.
The real commercial option for reaching Columbus is Indianapolis International Airport, roughly forty-five miles to the north, which carries the region's scheduled airline service along with actual airline lounges and more developed traveler facilities than a field like Columbus Municipal could ever support. Anyone flying in for the architecture, for Cummins business, or for any other reason should route through Indianapolis and rent a car or arrange ground transport for the drive south, since no scheduled shuttle links the two airports directly.
Travel to Columbus tends to track its architecture and design calendar more than any seasonal weather pattern: Exhibit Columbus, when it runs, and general architecture-tourism interest bring a modest but steady stream of visitors through Indianapolis rather than through the local airfield, and self-guided walking or driving tours of the city's buildings are the norm. Whatever draws you to Columbus, plan your actual flight into Indianapolis, confirm ground transport in advance, and treat Columbus Municipal Airport as a general-aviation field rather than part of your travel itinerary, since it was never designed with visiting tourists in mind.