United Airlines is raising the price to check bags, becoming the latest carrier this year to hike a fee that generated more than $5 billion for airlines in the first nine months of 2023 alone.United economy passengers who book domestic tickets starting Feb. 24 will pay $40 for a first checked bag, or $35 if they prepay online at least 24 hours before their flight, an increase of $5. A second checked bag will cost $50 at the airport, or $45 in advance. In 2020, United raised the price to check a bag at the a ...