German flagship carrier Lufthansa has announced plans to expand co-operation with JetBlue Airways (JBLU) in a move that may irk rivals such as Delta Air Lines Inc. (DAL), AP reported. Lufthansa and JetBlue plan a code-share deal from early October, a move that will leverage the U.S. carrier's strong position at New York's John F. Kennedy airport. Deustche Lufthansa AG acquired a 19 percent stake in parent JetBlue Airways Group Inc. in January 2008, but planned cooperation required the U.S. airline to first upgrade some of its reservations technology. The planned tie had already raised concern from some rivals wary of efforts by members of the Lufthansa-led Star Alliance to boost their presence at JFK. Code-sharing is designed to make booking flights more convenient for passengers, as well as to add revenue for partner airlines. Lufthansa provides service from 22 North American gateways, while JetBlue flies to 10 international locations.