Log on to your airline's website and follow the link to online check in.
Present the airline with the information regarding your flight. The required information is different for each airline but almost always includes your flight number, departure date, departure city, last name, flight confirmation number and/or your email address.
Submit your information to check in for your flight. Your flight status will appear. If weather is threatening to delay your flight or your arrival or destination airport is closed due to weather problems you will be notified and asked to call a number for additional assistance. Otherwise, your flight will show up as on schedule. If upgraded seating is available you will also have the opportunity to upgrade your seating assignment for a fee.