Delta Air Lines (NYSE: DAL) has put hundreds of flights nationwide on sale for fall 2012 as it celebrates the completion of its historic expansion at New York\'s LaGuardia Airport. \"Our LaGuardia expansion is truly a momentous occasion for Delta, and to celebrate we\'ve put fares on sale across the U.S.,\" said Gail Grimmett, Delta\'s senior vice president – New York. \"That means our customers in New York, Boston, Chicago, Atlanta and other cities nationwide can join in the celebration when they fly Delta this fall.\" This month, Delta completed the final phase of its LaGuardia expansion, which added 100 new daily nonstop flights – the single largest airline expansion at LaGuardia in decades. Today, Delta operates more than 260 daily flights to 60 cities from LaGuardia, significantly more than any other airline. Delta also is investing significantly in upgrading its airport facilities in New York, including a $160 million modernization at LaGuardia and a $1.2 billion expansion and enhancement of its terminal at John F. Kennedy International Airport, where the airline operates an international hub. From delta