United Airlines is an American airline and one of the biggest airlines in the world, its headquarters located in Chicago, Illinois. United Airways Flight was named Varney Air Lines when it was founded in 1926. Today, the airline flies to more than 340 locations from its hubs at O'Hare International Airport in Chicago, George W. Bush Intercontinental Airport in Houston, Los Angeles International Airport, Narita International Airport in Tokyo, Denver International Airport, Antonio B. Won Pat International Airport in Guam, Newark Liberty International Airport, San Francisco International Airport and Washington Dulles International Airport.
Of its many routes, some of the most popular United Airlines flights are those to Los Angeles, Hawaii and San Francisco. To serve its many routes, the company operates more than 700 aircraft, with the largest being the Boeing 737s. There is also other smaller Boeing and Airbus airplanes that make up the fleet. United Airlines is an affiliate of the Star Alliance and is one of the founding members.
Online check-in is available to passengers travelling on United Airlines flights. This opens 24 hours before a flight is scheduled to take off and closes 1 hour before scheduled departure. Online check-in can be done on a mobile or a web browser using an e-ticket number or confirmation code. To be able to check in online for a United Airlines flight, passengers must be able to fulfil certain criteria such as having no more than 9 people in their reservation, be taking less than 4 flights, and have a first flight operated by United Airlines. Online check-in is not available for passengers needing special assistance.