United Airlines is launching a new tiered fare system for its premium cabins, offering a lower-priced way to sit up front. The airline will introduce three fare types for its luxury seats, base, standard and flexible, across long-haul international, transcontinental and select Hawaii flights. However, this may require passengers to give up perks such as prime seat selection, extra checked bags, flexibility to change flights, and access to United's exclusive Polaris lounges. Base-level Polaris passengers will be bumped down to standard United Club access, while only those who pay for standard or flexible fares will get the full lounge experience. The changes are designed to make it easier to shop for flights and are expected to debut in select markets later this year. Some frequent flyers have criticized the move, while others argue it may come with strings attached.