While ancillary fees have crept upward in the last few years, Frontier Airlines is going against the trend and decreased its fee to check a second bag one way from $30 to $20. Baggage fees to check a first or second bag on Frontier Airlines now match those charged by Alaska Airlines–$20 per bag. Passengers who check a third bag, however, will be charged $50 on Frontier and only $20 on Alaska. Legacy carriers charge around $25 for a first bag and $35 for a second bag, which means non-elite passengers on Frontier can save $40 when checking two bags roundtrip compared to travelers checking two bags on American Airlines, for example, where the roundtrip fee would be $120. As always, Summit and Ascent members and travelers flying on Classic or Classic Plus fares can check two bags for free.