United will have the authority to fly scheduled airline service from Miami and New York if/when Fidel Castro dies and normal political relations are established with the U.S. United received Pan Am's dormant rights to fly: Miami-La Havana and New York-La Havana.
As a matter of fact, United is known to operate charters to Havana from Miami with 747s and 767s occasionaly.
Recently, The U.S. government allowed for direct Charter flights to be re-instated between the U.S. and Cuba. These flights can only been flown by Cuban Americans wishing to return to their place of birth and for special reasons. American citizens are still prohibited from traveling and spending money in Cuba. Therefore, Many Americans and Cuban Americans loop-hole the system by flying to Mexico and connecting at either Mexico City, Cancun or Merida with Mexicana, AeroCaribe or Cubana flights to Havana. Once in Havana, there is no problem as Cuban custom agents will not stamp your passport, if you just let them know. No questions asked! This is due to the fact that Cuba is in desperate need of cash and will do anything to attract tourist.
TACA has recently started a once a week service from Los Angeles and New York to Havana. While many American air carriers like: United, American and Continental can be seen in Cuban Airports because they are flying charters with Cuban American ex-pats returning to their homeland. That explains the reason why you find that Continental plane at Havana.
Pan Am - The World's Most Experienced Airline.