From which cities can I fly to Cuba? What are the restrictions for United States citizens? Thank you.

Despite the conventional wisdom that it is illegal for citizens of the United States to travel to Cuba, it is not. The restriction is on “travel-related transactions pursuant to travel to, from, and within Cuba,” according to the State Department Web site. And there are some exceptions to this de facto ban on spending money there.

The Treasury Department can issue special licenses for those traveling to Cuba for reasons including traveling in professional or educational roles. That’s how Caren Osten Gerszberg managed her trip in late 2006, when she joined a group organized by the Westchester Jewish Center of Mamaroneck, N.Y., to visit Jewish communities in Havana — including Adath Israel, Cuba’s only Orthodox synagogue — and other parts of the country (“In Cuba, Finding a Tiny Corner of Jewish Life,” Feb. 4, 2007).

Although such a trip allows travelers to bypass United States restrictions on tourism to Cuba, it requires a full schedule of religious and humanitarian activities that often require donations of medicine, clothing or religious objects needed for prayer.

Though plenty of Americans dodge the restrictions on travel to Cuba by flying there from airports in Mexico, Canada and Nassau — a somewhat risky strategy that Seth Kugel, a frequent Travel section contributor, wrote about in “Cuba: You Can’t Get There From Here …” (Nov. 14, 2003) — others are looking forward to the day when those restrictions are dropped, perhaps once Fidel Castro dies.

Chief among them are hotel and cruise-line executives who see a huge pent-up demand for travel to this long-off-limits country and are already checking out sites where they can build new hotels or dock their ships. You can read about those plans for a post-Castro Cuba in “Waiting for Havana” (Nov. 27, 2005), by Luisita Lopez Torregrosa. (All these articles can be found at nytimes.com/travel.) - DAVID G. ALLAN