High Cross Farm became an airport in August 1939, and the conversion was as humble as it sounds. Photographs from the opening show a small group of dignitaries - Earl Amherst representing Great Western and Southern Air Lines, the chairman of the Isles of Scilly Steamship Company, the captain of the local golf club - standing on freshly graded ground. There was no glamour to the project. The Isles of Scilly needed a faster link than the Penzance steamer, and a flat patch of west-facing Cornish granite was what they had to work with. The Dragons that had been touching down on the golf course since 1937 now had a dedicated strip, and within months the airfield was at war.

Great Western and Southern Airlines took over the route in 1938, replacing the original twin-engined Dragons with the slightly larger de Havilland Dragon Rapides during the war years. These were fabric-and-plywood biplanes, designed for short hops to communities that no other aircraft could reach. They flew through everything the Atlantic threw at them - low cloud, gale-force winds, the kind of visibility that would ground modern airliners. In February 1947 British European Airways absorbed the operation. The Dragon Rapides kept flying the Land's End route until 1964, when BEA replaced them with a single Sikorsky S-61 helicopter operating from a new heliport at Penzance. For the next forty-eight years, helicopters defined the journey to Scilly.

On 16 July 1983, a British Airways Helicopters Sikorsky S-61 on a routine scheduled flight from Penzance crashed into the sea two nautical miles short of St Mary's Airport. Nineteen passengers and one crew member were killed. Six people survived - four passengers and two crew - pulled from the cold Atlantic by the St Mary's Lifeboat, the same RNLI station that has guarded these waters since 1837. The crash remains one of the worst civilian helicopter accidents in British history. The Penzance helicopter service continued after the disaster but ended entirely in 2012, and a new commercial helicopter operation only resumed in 2020. For islanders, the route between mainland and home has always carried risk; the 1983 crash made that risk impossible to ignore.

A public footpath crosses within a few metres of the southern end of the runway, and it is closed by warning lights and bells a few minutes before each take-off or landing. Walkers stop, the bells ring, a small twin-engined Britten-Norman Islander or de Havilland Twin Otter from Isles of Scilly Skybus thunders past at head height, and then the lights go green and life resumes. The airport doubles as a base for emergency services - the Cornwall Air Ambulance, the HM Coastguard Search and Rescue aircraft from Newquay, the Isles of Scilly Fire and Rescue Service. In 2014 the European Commission approved a £6.5 million upgrade for runway resurfacing, new navigational aids, and terminal improvements. The little airfield is still a working farm of a place, set into the landscape rather than imposed on it, but it is also the lifeline that keeps these islands inhabited year-round.