Mobile bar codes and check-in are the newest convenience being offered to United Airlines customers. Customers can no check-in online up to 24 hours before their flight. Certain airports are supporting the mobile boarding pass which involves the customer using a mobile bar code from their phone in place of a paper boarding pass. The 2D barcode can be presented at the five hubs of United as well 10 other airports with five more scheduled to launch the program in the weeks to follow. This 2D mobile bar code technology was recently been implemented at American Airlines as well, which may be a sign that it is only a matter of time before this option becomes far more common among airlines.