Get round-trip flights on Southwest Airlines with rates from $114 on Airfarewatchdog. We found the lowest fares on flights between Chicago and Boston. Sunday fights from New York to Chicago start at $128, and flights from Los Angeles to Las Vegas start at $118. You can enter your own travel dates and locations to find fare prices on Airfarewatchdog. Some of these flights need to be booked at least 21 days in advance and require travel on specific days of the week. Prefer to book a vacation package with the airline? There's a summer travel promotion going on at Southwest Vacations, too. Taxes, fees, and restrictions may apply.