Low-fare/high-frills JetBlue is doubling up on flights from its two Florida focus cities to Mexico City as part of a push to build up services to Latin America and the Caribbean. From September 6,  there will be two daily roundtrips each on the Orlando-Mexico City and the Fort Lauderdale/Hollywood-Mexico City routes. Fast-moving business travelers like more flight frequencies, the better to change plans quickly when work dictates.   Right now, JetBlue is operating those routes with once-daily nonstops. JetBlue fields flights to 60 nonstop destinations from Fort Lauderdale/Hollywood International. It operates nonstop service to 30 destinations out of Orlando, although a significant chunk of those passengers are leisure travelers. Latin America is no afterthought among JetBlue planners A full one-third of the airline’s flying capacity is devoted to Latin America and Caribbean flights. By year’s end, it intends to operate 315 daily flights in the region.