Sanctions are crazy! They just ensure that an unpopular foreign leader stays in power, ensuring America has a few bad guys to posture with - Castro has been in power since Eisenhower, Kennedy, Johnson, Nixon, Ford, Carter, Reagan, Bush 1, Clinton, Bush 2 and counting. Saddam since Bush 1, Clinton, Bush 2 and has a while to go yet, ditto Qadaffi. If there were no sanctions these useless people would never have retained their grip on power. (By 'useless people' I refer to the foreign despots - although most of the Presidents could fit into that category, that wasn't what I meant.) If America maintained full relations with these countries increased wealth from increased trade would give their populations more freedom, information and stronger opposition parties. It hurts American companies too, they'd make a mint in Cuba or the oil-producing nations. None of the countries America has picked are 'poor' by definition, in fact some were the richest in their region - Iran, Lebanon, Cuba, Libya all had (in some cases still have) living conditions comparable to most first world nations, at least for a big chunk of their population if not all.
Anyway, it's silly not to allow US carriers into Cuba, even sillier for US-based CRS' (ie Sabre) not to even have Havana loaded as a destination. Castro is barely even a threat to his own people, certainly not to anyone else.
BTW, didn't Miami Air run a quasi-scheduled service from (wait for it) Miami with 727-200s?
(Sorry for the rant Johan!)
fly Saha Air 707s daily from Tehran's downtown Mehrabad to Mashhad, Kish Island and Ahwaz