No tickets have been sold, no money collected and no advertising — aside from the Nov. 4 announcement — has taken place, said Hauf. Still, he wishes he'd filed the prospectus sooner.

"We hope this won't delay anything, as a result of this misunderstanding," said Hauf. "The truth is, I should have been more cautious."

Smith, the Department of Transportation attorney, would not discuss potential penalties if the agency determines any advertising rules were violated.

In mid-August, the agency fined a company for violating the agency's rules governing charter flight advertising in 2009. According to an agency statement, Atlanta-based Aviation Advantage Inc. was fined $150,000 for several violations, including promoting flights "without listing the name of the charter operator or the airline operating the flights, as required by DOT rules."

Travel to Cuba from the U.S. has been restricted since 1961, soon after Fidel Castro took power and nationalized American businesses on the island.

Cities that now offer flights to Cuba include New York, Miami, Atlanta, Chicago and Tampa.

The Island Travel flights from Baltimore will operate at fixed times on Wednesdays and will take about three hours and 15 minutes, said Hauf. Because of complicated ticketing requirements and hefty charges to land in Cuba, a round-trip ticket to Cuba will cost about $800, he estimated.

Hauf said he expects the flights from Baltimore to mainly serve diplomats, nonprofit organizations and academics. Maryland does not have a large Cuban-American population like that of other metro areas currently served by charter flights to Cuba.

Earlier this month, Dean said that the Island Travel flights would apparently be the first nonstop service ever between BWI and Havana. The airport has no record of scheduled service before Castro came to power, he said.

About a decade ago, charter flights between the cities were exchanged when the Orioles played Cuba's national baseball team.