Prinair was Puerto Rico's domestic and international airline for 3 decades.

Service started in 1966, under the name Aerolineas de Ponce. The initial services were from Mercedita Airport in Ponce to Luis Munoz Marin International Airport (then known as Isla Verde International Airport) in San Juan. The company's name was changed to Prinair the following year (Puerto Rico INternational AIR lines).

Prinair de Havilland Heron at San Juan-Luis Munoz airport, Puerto Rico. Photograph taken July 1972.

The airline used Heron turbo-props for its services. The livery reminded the public of Braniff International because of the many different colors used. During the 1970s, expansion saw the airline start services to Opa Locka, a Florida location close to Miami, Santo Domingo, the Virgin Islands, Martinique, Barbados, Puerto Plata, and many other Caribbean destinations, as well as Vieques, Mayaguez, Culebra and Aguadilla on the domestic side.

Prinair suffered 2 fatal accidents (including flight 191) that took away some of the public's trust in the airline. The first was while landing in Mayaguez's Eugenio Maria De Hostos airport, where all 9 passengers died, and the second one in Santurce, a San Juan area near Luis Munoz Marin International Airport, where 5 passengers perished, and 4 people, including local mechanic Luciano Rivera, were injured on the ground.

In the 1980s Prinair introduced service with the larger and more capable Convair turbo props. This provided the plane spotter at San Juan with another interesting airplane to look out for, but did little for the airline, although it did help increase the earnings from the Virgin Islands routes. Increased competition for these routes in the shape of Aero Virgin Islands and Oceanair, plus some distrust from the public that still had not forgotten the fatal crashes, caused Prinair to cease operations in November, 1984.