 During the early 1970s, Caribair's roundtrip DC-9 jet service between Miami and San Juan made intermediate stops in Santo Domingo, Port-au-Prince, Kingston and Montego Bay.In June 1970, the Puerto Rican Air National Guard apparently received reports concerning a mystery object from a Caribair jet as well as from a Pan American World Airways (Pan Am) jetliner.Pilots in both aircraft reportedly claimed to have seen an unidentified flying object (UFO) close to San Juan's Isla Verde International Airport.