By Paul Wiseman, AP Business WriterWASHINGTON -- Airlines cancelled hundreds of flights as Tropical Storm Isaac lashed southeastern Florida Sunday, with service not expected to resume fully until late Monday. The airports in Miami and Fort Lauderdale were hit the hardest, cancelling 589 flights -- the vast majority of the 742 U.S. flights grounded overall because of the storm as of Sunday afternoon, according to the flight-tracking service FlightAware. American Airlines and its American Eagle affiliate cancelled 486 flights. The last American flight left Miami at noon Sunday. The airline expects to be fully operational out of Miami by noon Eastern time on Monday, said airline spokesman Matt Miller. American runs a hub in Miami, a jumping-off point for flights to the Caribbean and Latin America. Overall, airlines have cancelled 184 flights for Monday but expect to be operating normally by late Monday, according to FlightAware. > > Bull or Bear? Vote in Our Poll Isaac, already carrying winds of more than 60 miles an hour, was expected to cross the Keys by late afternoon. The storm will likely pick up strength from the warm, open waters of the Gulf of Mexico and strike as a dangerous Category 2 hurricane somewhere between New Orleans and the Florida Panhandle on Wednesday, the seventh anniversary of Hurricane Katrina. Louisiana Governor Bobby Jindal declared a state of emergency ahead of Isaac late Sunday and urged voluntary evacuations for coastal parishes in the state. Inside the American Airlines terminal in Miami, travelers craned for a look out of one of the doors as Isaac pelted the airport with strong rain and wind. At Fort Lauderdale-Hollywood International Airport, the check-in line at the Southwest Airlines ( LUV) counter was completely empty at 7 a.m. Typically at that time on a Sunday the area is jammed, mainly by people leaving from vacations and cruises. Delta Air Lines ( DAL) dropped three round-trip flights between its Atlanta hub and hard-hit Key West. "No others as of yet," Delta spokesman Morgan Durrant said by email Sunday afternoon. "We anticipate running a full schedule with the exception of Key West." United Airlines ( UAL) and its United Express affiliate dropped 26 flights in the path of the storm.