On 22 September 1946 a four-engined Douglas DC-4 lifted off from Madrid and turned south. Thirty-six hours, three stops and one unscheduled diversion later it landed at Morón in Buenos Aires. Iberia had just become the first European airline to link the old continent with South America after the Second World War, and it had done it on an aeroplane built to haul cargo across the Pacific.

Eighty years later the same city pair is three Airbus A350 departures a day and twelve hours block time. The gap between those two operations is the whole history of long-haul flying compressed into one route.

What makes the 1946 crossing worth revisiting is not the record. It is the detail: the astrodome, the storms flown underneath rather than over, the Brazilian paperwork nobody had filed, and the six-year-old boy who was shown two live leopards at a refuelling stop in the Spanish Sahara.

A cargo hauler pressed into airline service

The DC-4 that flew the route was a war-surplus design. Douglas built it as the C-54 Skymaster, the type that moved men and freight across the Atlantic and Pacific for the US Army Air Forces, and after 1945 it flooded onto the civil market at prices no new airliner could match. Iberia bought into that market like everybody else.

The specification looks modest now. Four Pratt & Whitney R-2000 Twin Wasp radials, a wingspan of 35.82 metres, a top speed of 450 km/h, 44 seats, and a range a little under 6,800 kilometres. It was unpressurised, which is why the crossing was flown low, and why storms had to be gone through or around rather than above.

Thirty-six hours, and a stop nobody planned

The route went Madrid to Villa Cisneros in the then-Spanish Sahara, then the long jump to Natal on the Brazilian bulge. That leg alone, the actual crossing of the ocean, took about thirteen hours. From Natal the plan was to run down the coast to Buenos Aires.

It did not go that way. The aircraft was diverted into Rio de Janeiro to sort out Brazilian entry formalities that had never been started before departure from Spain. The first Europe to South America service of the post-war era was held up by paperwork, which is either a disappointing detail or the most honest one in the story.

Navigation over the ocean was done the old way. The DC-4 carried a navigator, Indalecio Rego, who took astronomical sights through a glass astrodome in the cabin roof to fix the aircraft’s position. The role was new to Iberia; the Madrid to Buenos Aires route is what forced the airline to add it.

What a 1946 crossing actually cost

Iberia’s own anniversary material puts the 1946 fare at 11,435 pesetas outbound from Spain, or 3,381 Argentine pesos from the other end, with 114.35 pesetas charged for each checked suitcase. A Spanish Ministry of Public Works history published for the route’s seventieth anniversary gives 7,250 pesetas. Both figures circulate; the difference probably reflects different cabins or different points in the first year, and we have not found a document that settles it.

Run the higher figure through inflation and you land near 17,800 US dollars in today’s money. Iberia currently sells the same journey for roughly 1,000 to 1,200 dollars return in economy and around 5,600 in business. That is the compound interest of eighty years of engineering.

For the money, passengers got fried chicken, Spanish omelette, hard-boiled eggs and a chocolate in a cardboard box. Drinks were free. They also got a night in a parador at Villa Cisneros, built specifically so that travellers on the return leg had somewhere to sleep.

The passengers, and the boy with the leopards

The 22 September flight was a route-proving and inaugural run rather than a commercial service. On board were Iberia directors, Spanish government representatives, technicians and company staff. Scheduled operations with fare-paying passengers began on 15 October 1946 as service 1215, at first once every ten days, with an extra stop at Montevideo added at Uruguay’s request. Demand pushed it to weekly before long.

Cabin service on those first flights was run by Iberia’s first stewardesses: Encarnación Ruiz de Gámiz, Pilar Macías, María José Ugarte and Ana Marsans. What to call them was genuinely debated inside the company, with aeroviarias, aeromozas, mayordomas and provisadoras all proposed before the Spanish settled on azafata.

The only child aboard the inaugural flight was Francisco Botas, six years old, from A Coruña, travelling with his mother to meet Argentine relatives. In interviews given decades later he recalled a stewardess who stayed with him the whole way and gave him a toy car, being taken to the back of the cabin during turbulence and shown star charts to distract him, and a visit to the cockpit. What stuck most was the stop in the Spanish Sahara, where the passengers ate at the house of the governor of Villa Cisneros and he saw two live leopards.

The competition arrived immediately

Spanish emigration to Argentina made the route commercially obvious, and Iberia’s head start lasted months rather than years. KLM came in, then Argentina’s FAMA, the forerunner of Aerolíneas Argentinas, then British South American Airways, Air France and Panair do Brasil.

Between them they killed the transatlantic liner as a way of getting between Europe and South America. A sea crossing took more than a month and depended on the weather. Thirty-six hours in an unpressurised DC-4 sounds brutal until you price the alternative in weeks.

Iberia followed Buenos Aires with Madrid to New York on 3 August 1954. The South Atlantic came first, which is unusual: most airlines built the easier North Atlantic franchise before reaching further.

Eighty years on

Iberia marked the anniversary on 22 September 2026 with dulce de leche desserts in the cabin, which is a modest gesture for a route that has run continuously for eight decades. The airline now operates three daily Madrid to Buenos Aires flights, mostly with A350-900s, rising to four a day in June, July and August.

Twelve hours nonstop at 38,000 feet, above the weather, with two engines instead of four and no navigator taking star sights through a dome in the ceiling. The route is the same. Nothing else about it is.

Sources: Iberia press release, 22 September 2026; Aviacionline, “80 years ago, Iberia flew to Buenos Aires for the first time”, 22 September 2026; Marián Campra Ga de Viguera, “70 años del primer vuelo comercial Madrid–Buenos Aires”, Spanish Ministry of Public Works, February 2017; Wikipedia, “History of Iberia (airline)” and “Douglas DC-4”.