Both Aeromexico and Copa Airlines have round trip airfares travelling from Los Angeles (LAX) to Sao Paulo Brazil (GRU) for $838, making 1 stop. For Aeromexico the stop would be in Mexico city and for Copa, it would be Panama.
Departs LAX: April 4-19, 25-30; May 1-31; June 1-3
Returns good and wide availability thru mid-June, generally 7 day stay okay
Use dates and book it on Expedia [expedia.com]
. Bundling hotel with airfare will save money.
Copa Airlines [copaair.com]
is a Star Alliance member.