Get up to $20 off Round-Trip Flights when you use the code OT20 on the checkout screen at OneTravel. We tried this out on an America Airlines flight from Chicago to Las Vegas in mid-February. This deal took the total price from $239.15 to $220.15. Enter your own origin city and destination when you Search for Fares. Then enter the code in the "Price Details" section of the payment page. Book by 11/4. Taxes, fees, and restrictions may apply.