Cusco (CUZ) is the nearest major airport to breathtaking Machu Picchu
Travel is valid on limited dates from late August through October.
Read about using ITA Software here as that can really make it easy to find cheap dates besides for the sample dates listed below.
Washington DC-Cusco on 08/25-09/03 is $397.99
JFK-Cusco on 09/04-09/11, 09/08-09/11, 09/14-09/17, or 09/18-09/21 is $482.99
Los Angeles-Cusco on 08/25-09/02 is $554.99
Other departure cities work as well.