United Airlines flies between: London ON - Chicago, Quebec City - Chicago, Toronto - New York, Toronto - Los Angeles, Toronto - Boston, Vancouver - Los Angeles, Toronto - San Francisco, Toronto - Orlando, Toronto - Miami, Toronto - Chicago, Toronto - Newark, Vancouver - San Francisco, Montreal - New York, Toronto - Las Vegas, Calgary - Phoenix, Montreal - Chicago, Toronto - Atlanta, Toronto - Phoenix, Calgary - Los Angeles, Montreal - Boston, as well as several other routes.
Generally speaking, you are likely to have to pay for your checked baggage on United. If you are flying to a destination within Canada, the USA or any of its territories such as Puerto Rico or the US Virgin Islands, your first check bag will cost you $25 and if you fly with a second checked bag, it will cost you $35. These fees are per direction, so expect to pay double that for a round trip journey. If you are flying United anywhere else, your first bag will be free. You are allowed one carry-on and one personal item.