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United Airlines

One of the world's largest airlines, flying from eight US hubs

  • United StatesCountry
  • UAIATA Code
  • UALICAO Code
  • Star AllianceAlliance
  • Full-ServiceAirline Type

Guide reviewed

About United Airlines

United Airlines is one of the world’s largest airlines and a founding member of Star Alliance, flying from Chicago, Denver, Houston, Newark, San Francisco and other hubs to every inhabited continent. On most domestic flights, Basic Economy includes only a personal item, and since April 2026 the first checked bag costs up to $50. This guide covers fares, bag fees, power banks, MileagePlus and how United compares with Delta and American.

United traces its history to 1926, is based in Chicago and was a founding member of Star Alliance in 1997. It has one of the largest international networks of any US airline.

United Airlines flights to Chicago
Photo: Max Bender / Unsplash

Check-In and the United App

Online check-in opens 24 hours before departure on the website and the United app, which also offers mobile boarding passes and bag tracking.

Arrive at least two hours before domestic flights and three hours before international ones, especially at Newark and San Francisco.

Power Banks on United Flights

United follows US FAA lithium battery rules:

  • Power banks and spare batteries go in your carry-on or personal item, never in checked bags.
  • Up to 100 Wh is allowed; 100–160 Wh needs approval, with a maximum of two spares.
  • Take power banks out before a bag is gate-checked.

On Star Alliance partners such as Lufthansa or Singapore Airlines, stricter rules apply, including bans on using power banks on board.

Families, Special Assistance and Pets

Children under 12 can sit next to an accompanying adult at no extra cost in Economy, including Basic Economy, when booked together. Infants under two can travel on an adult’s lap on domestic flights.

Special assistance should be requested in advance. Small cats and dogs can travel in the cabin for a fee.

How to Find Cheap United Flights

United Airlines flights to Denver
Photo: Bill Griepenstroh / Unsplash
  • Check the carry-on rule: on domestic Basic Economy, the $75 gate fee for a carry-on can wipe out the saving.
  • Prepay bags: paying at least 24 hours ahead is cheaper than at the airport.
  • Compare hubs: connecting via Denver or Houston can be cheaper than nonstop.
  • Avoid peaks: Thanksgiving, Christmas and summer weekends.
  • Compare airlines: use the FlightSelects flight search to see United next to Delta, American and others.

United vs Delta vs American

The three big US network airlines each lead a different alliance.

UnitedDeltaAmerican
Largest hubsChicago, Denver, HoustonAtlantaDallas Fort Worth
AllianceStar AllianceSkyTeamoneworld
LoyaltyMileagePlusSkyMilesAAdvantage
Basic Economy carry-onPersonal item only (most domestic)IncludedIncluded
Domestic first bag$50 ($45 prepaid)$45$50

See our Delta guide and American Airlines guide to compare.

Arriving in Chicago

Chicago O’Hare is about 27 km from downtown. The CTA Blue Line train runs 24 hours to the Loop, and taxis and ride-hailing apps are available.

You can also book an airport transfer in advance at a fixed price.

Is United Airlines a Good Airline?

Yes. United has a huge global network, a strong app, miles that never expire and Star Alliance connections. Domestic Basic Economy is one of the most restrictive in the US, so check the carry-on rule before you buy.

For more options, see our Lufthansa guide, our airline guides and the FlightSelects travel blog.

Facts checked in October 2026 against NerdWallet’s United bag fee guide. Fees change, so check the official United Airlines website before you travel.

Star Alliance & Airline Partnerships

United is a founding member of Star Alliance (1997). You can connect onto partners such as Lufthansa, Air Canada, ANA and Singapore Airlines on one ticket and earn or spend MileagePlus miles across the alliance.

Learn more about Star Alliance

Codeshare & Interline Partnerships

United runs joint ventures with Air Canada and the Lufthansa Group across the Atlantic, with ANA across the Pacific and with Air New Zealand, and has many codeshare partners worldwide.

Hubs & Focus Cities

United operates from eight hubs. Chicago O'Hare, Denver, Newark and San Francisco are among the largest, while Houston, Washington Dulles, Los Angeles and Guam add further domestic and long-haul connections.

Popular United Airlines Routes

United's busiest routes link its big hubs coast to coast and to Hawaii, alongside major long-haul routes to London, Frankfurt, Paris and Tokyo. Choose a route to see recent schedules and fares.

Fares are the lowest recently found by our partners and can change quickly. Select a fare to check live prices and availability.

United Airlines Reschedule & Cancellation Policy

On United, the main thing to know is the difference between Basic Economy and every other fare. Since 2020, Economy and premium cabin tickets for most trips starting in the US have no change fee: you pay only the fare difference if the new flight costs more. Basic Economy, on the other hand, can't be changed or refunded.

If you cancel a non-refundable Economy ticket, the value usually comes back as a future flight credit. Fully refundable fares can be cancelled for money back.

  • Basic Economy No changes and no refunds, except within the 24-hour window.
  • Economy and premium cabins No change fee on most trips from the US; fare difference applies.
  • Cancelling a non-refundable ticket The value is normally returned as a future flight credit.
  • Refundable fares Can be cancelled for a refund to the original payment.
  • 24-hour rule Tickets booked at least 7 days before departure can be cancelled for a full refund within 24 hours of booking.
  • Same-day changes Economy and higher can switch to another flight on the same day, for a fee or free for higher Premier members.
  • If United cancels or significantly changes your flight You can choose rebooking or a refund.
  • How to change or cancel Use My Trips on united.com or the United app.

United Airlines Seat Selection & Additional Services

Basic Economy seats are assigned at check-in unless you pay to choose one. With standard Economy you can pick a regular seat for free, or pay for Economy Plus, which has extra legroom, and preferred seats near the front.

United sells upgrades to Premium Plus and Polaris on many flights, and MileagePlus Premier members get complimentary upgrades on domestic flights. Online check-in opens 24 hours before departure on united.com and in the United app.

  • Basic Economy Seats assigned at check-in; advance seat selection is paid.
  • Economy Standard seats free to choose.
  • Economy Plus Extra-legroom seats for a fee or included with Premier status.
  • Preferred seats Front-of-cabin Economy seats for a fee.
  • Premium Plus Premium economy on long-haul flights.
  • United Polaris Lie-flat business class with Polaris lounge access on long-haul routes.
  • Online check-in Opens 24 hours before departure.
  • Wi-Fi and entertainment Available on most flights; free entertainment in the United app.
  • Special assistance Request wheelchairs and other help when booking or in My Trips.

United Airlines Baggage Allowance

United raised its bag fees in April 2026. On domestic US flights, Economy tickets don't include a free checked bag, and Basic Economy allows only a personal item, not a full-size carry-on. On transatlantic and transpacific routes, Economy usually includes a checked bag and Basic Economy includes a carry-on.

Economy bags can weigh up to 23 kg (50 lb) and measure up to 158 cm (62 in). Paying for bags online at least 24 hours before departure is cheaper than at the airport, and MileagePlus Premier members and United credit card holders get free checked bags.

  • Carry-on (Economy and up) 1 bag up to 56 × 35 × 22 cm (22 × 14 × 9 in) plus 1 personal item.
  • Personal item Up to 43 × 25 × 22 cm (17 × 10 × 9 in), fits under the seat.
  • Basic Economy (domestic) Personal item only; a full-size bag brought to the gate costs $75.
  • Basic Economy (transatlantic, transpacific, South America) Full-size carry-on included.
  • Domestic first checked bag $50 at the airport, less if prepaid at least 24 hours before departure.
  • Domestic second checked bag $60 at the airport, or $55 prepaid.
  • Long-haul international (Economy) First bag usually free; second bag $100.
  • Overweight 50–70 lb bags cost up to $100 extra in Economy; Premier members and premium cabins get 70 lb free.
  • Free bags Premier members, Star Alliance Gold and eligible United cardholders.

MileagePlus: United Airlines Loyalty Programme

MileagePlus is United's free loyalty programme. You earn miles on United and Star Alliance flights, with credit cards and through partners, and redeem them for flights, upgrades and more. MileagePlus miles don't expire.

Frequent flyers can earn Premier status in four published tiers: Premier Silver, Premier Gold, Premier Platinum and Premier 1K. The very top flyers may be invited to Global Services.

  • Premier Silver Free Economy Plus at check-in, priority services and Star Alliance Silver status.
  • Premier Gold Star Alliance Gold, with lounge access on international Star Alliance trips and extra baggage.
  • Premier Platinum Higher upgrade priority and more benefits.
  • Premier 1K United's top published tier, with the best upgrade priority and PlusPoints for upgrades.
  • Miles never expire Your miles stay valid regardless of account activity.
  • Free Wi-Fi United is adding free Starlink Wi-Fi for MileagePlus members on more and more aircraft.
  • Star Alliance Earn and redeem miles on all Star Alliance airlines.
Join or log in on the United Airlines website

United Airlines: Frequently Asked Questions

01What are United Airlines’ IATA and ICAO codes?

The airline's two-character IATA code is UA. It appears in flight numbers (for example UA 101), on tickets and on airport departure boards. Its three-letter ICAO code is UAL, which air traffic control and flight-tracking services use to identify the airline.

02Which airline alliance is United Airlines part of?

It is a member of Star Alliance. Alliance membership usually means easier connections, shared lounge access for eligible passengers and the option to earn and redeem miles across partner airlines.

03Where is United Airlines headquartered?

The airline is headquartered in Chicago, United States.

04When was United Airlines founded?

The airline was founded in 1931.

05What are United Airlines’ main hubs?

Its main hubs and focus cities are: Chicago (ORD) – Hub & Headquarters; Denver (DEN) – Hub; New York/Newark (EWR) – Hub; San Francisco (SFO) – Hub.

06Does United Airlines offer online check-in?

Yes. Online check-in is available through the airline's official website. Check-in opening and closing times depend on the route and airport, so confirm them for your flight before you travel.

07What is the difference between United Basic Economy and Economy?

Basic Economy is United's cheapest fare. On domestic flights it allows only a personal item, seats are assigned at check-in, and the ticket can't be changed or refunded. Standard Economy includes a carry-on, free seat selection and changes without a change fee on most trips.

08Does United charge for checked bags?

On domestic US flights, Economy and Basic Economy pay for checked bags; prepaying online is cheaper. Most long-haul international Economy fares include one checked bag. Premier members and eligible United cardholders get free bags.

09Does United have change fees?

Not for Economy and premium cabins on most trips from the US; you pay only the fare difference. Basic Economy can't be changed.

10What size carry-on does United allow?

One carry-on up to 22 × 14 × 9 inches (56 × 35 × 22 cm) plus one personal item up to 17 × 10 × 9 inches, except on domestic Basic Economy, which allows the personal item only.

11Do United MileagePlus miles expire?

No. MileagePlus miles don't expire, regardless of account activity.

United Airlines, its logo and trademarks are the property of United Airlines, Inc. and are used for identification and informational purposes only. FlightSelects is not affiliated with or endorsed by United Airlines unless expressly stated. FlightSelects may earn a commission when you book through partner links, at no extra cost to you.