LAS VEGAS (REUTERS) – – GE Aviation (GE.N) said on Monday it had teamed up with Textron (TXT.N) to produce an all-new turboprop aircraft and engine for the general aviation market, part of an effort GE expects will generate more than $1 billion in annual sales of engines by 2020. GE Aviation said its so-called advanced turboprop engine takes aim at a widely used engine by United Technologies (UTX.N) unit Pratt & Whitney known as the PT6, which has dominated the market for 50 years, producing 51,000 units.