Basic EconomyYou can't bring a carry-on bag unless you're flying to South America, across the Atlantic or across the Pacific. All other bags have to be checked. Note, if you check a carry-on at your gate, you'll be charged the standard bag fee plus an additional $25.
Economy Plus and upgrades: Travelers with Basic Economy fares are only eligible to purchase Economy Plus seating at check-in and are not eligible to purchase premium cabin upgrades, use their Economy Plus subscription benefits or purchase United Travel Options packages.
You can avoid United checked bag fees by paying more to travel in premium economy, business or first class. Passengers in these cabins receive two free checked bags on domestic flights. Those flying in business or first class have a 70-pound baggage allowance.
United is a good choice if you're looking to save money on international flights. They also have great Polaris Business Class perks and pretty good in-flight amenities. For example, United offers personal device entertainment, snack and beverage service, and meals for in-flight purchases.