Ecuador – Lima, Peru and a third flight that skipped Guayaquil. In 1949, Braniff flew direct via Lima to Rio de Janeiro, Brazil and La Paz, Bolivia. In 1950, Pan American World Airways (Pan Am) began nonstop Douglas DC-4 service to Mexico City. On October 1, 1950, Chicago and Southern Air Lines began flying new Lockheed Constellations nonstop to St. Louis and direct to Chicago Midway Airport. Chicago & Southern flew nonstop to New Orleans, the sole purpose being to connect to the airline's daily Douglas DC-4 "Caribbean Comet" flights between New Orleans and Havana, Cuba; Kingston, Jamaica and Caracas, Venezuela as Chicago & Southern did not then have local traffic rights between Houston and New Orleans. In 1953, Chicago & Southern (C&S) was acquired by and merged into Delta Air Lines, giving Delta access to Houston for the first time. In 1954, Delta, operating as "Delta C&S", was flying a daily Convair 340 Houston – New Orleans – Havana, Cuba – Port au Prince, Haiti – Ciudad Trujillo (now Santo Domingo), Dominican Republic – San Juan, Puerto Rico. Also in 1954, an expanded terminal building opened to support the 53,640 airline flights that carried 910,047 passengers. The airport was renamed Houston International Airport the same year. The April 1957 Official Airline Guide lists 26 weekday departures on Eastern, 20 on Braniff (plus four departures a week to/from South America), nine on Continental Airlines, nine on Delta Air Lines, nine on Trans-Texas Airways, four on National Airlines, two on Pan American World Airways and one on American Airlines. There were nonstops to New York City and Washington D.C., but not to Chicago or Denver or anywhere west of Colorado. Later in 1957, KLM Royal Dutch Airlines started Douglas DC-7C flights to Amsterdam via Montreal. In 1958, Delta was operating daily nonstop Douglas DC-7s to New York City and weekly DC-7s direct to Caracas, Venezuela via New Orleans (Delta called this latter service the "El Petrolero") while Eastern Douglas DC-7s and Lockheed Constellations flew nonstop to New York City. The jet age arrives Houston's first scheduled jets were Delta Douglas DC-8s nonstop to New York in December 1959 (Cearley says they began on December 1). Braniff International introduced Boeing 707s in April 1960, nonstop to Dallas Love Field and direct to Chicago O'Hare Airport; Braniff Lockheed L-188 Electra propjets flew nonstop to Chicago Midway Airport and Dallas Love Field, and direct