United Airlines flies between: Toronto - New York, Toronto - Boston, Toronto - Chicago, Toronto - Dallas, Montreal - New York, Toronto - Orlando, Toronto - Miami, Toronto - Los Angeles, Toronto - Phoenix, Toronto - Washington DC, Toronto - Washington DC, Montreal - Chicago, Toronto - Las Vegas, Toronto - Philadelphia, Vancouver - Honolulu, Vancouver - Los Angeles, Ottawa - Boston, Calgary - Houston, Toronto - Houston, Halifax - 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.