Airlines have been spending big to add more space and comfort to seats on board planes. According to AeroDynamic advisory, airplane seats were a $2.6 billion dollar market globally in 2022, almost half of $6.2 aircraft interiors market. U.S. airlines like American, Delta and United have been adding more premium seats to their fleets. CNBC got an inside look at how seats are made, and to find out why they are becoming an increasingly important part of an airline’s business.