Technically, there was still room for hope yesterday. In the summer months, someone from that plane - JFK himself, his wife Carolyn Bessette, and her sister, Lauren Bessette, might still have been breathing in those Atlantic waters, but common sense, and the belongings that had already washed up on a beach of fine sand on the island's westernmost edge, told a different tale. JFK Jnr was surely dead.
Thus, disbelief and grief have struck this land as it takes its summer holidays - just as it did Britain when the Princess of Wales died in August 1997. JFK was not royalty, but he was surely a prince. The only surviving son of the late President John F Kennedy, he was also America's favourite son: impossibly good looking, very rich and a perennial of gossip headlines and magazine covers.
Even his death - apparent death - was more poignant and more strange than the most fertile of tabloid imaginations could have mustered. He and the beautiful wife he married in 1996 were heading for Massachusetts for a wedding at the place where the American version of Camelot was born - the Kennedy Compound at Hyannisport on Cape Cod. To be wed was Rory Kennedy, the daughter of the late Robert F Kennedy who just 19 months ago watched her brother, Michael, die on the ski slope in Aspen.
And, as everyone on Martha's Vineyard wanted to remind you, yesterday was the 30th anniversary of the incident on Chappaquiddick that spawned the first Kennedy scandal, when a car driven by Edward Kennedy plunged off a bridge killing his passenger, Mary Jo Kopechne. This is no ordinary curse that the Kennedys are suffering, it is a curse with a gruesome sense of historical neatness.
And then there were those pieces of flotsam found by swimmers and sunbathers just after lunchtime on Saturday - a canvas suitcase bearing the Morgan Stanley business card of Lauren, a cosmetic bag, a prescription bottle with the name Carolyn Bessette on the label, a plane seat, a piece of a strut and the rubber covering from a pedal. They all washed up on Philbins Beach - less than two miles from the Martha's Vineyard house that JFK inherited from his mother, Jackie, after she died in 1994.
It was the bag they spotted first, bobbing in the slight summer swell. Damon Seligson, 30, from Boston swam out to fetch it. "We were standing on the beach, enjoying the day - a bunch of us were watching the waves and saw what looked like luggage floating in the water," he said. Aware that the planehad gone missing, he feared the worst. "My heart was pounding. I almost passed out."
When he retrieved it, the bag was wet but in tact, Lauren's business card still inserted in a sewn-on pocket. "We opened it to peek in and saw women's clothing, a make-up bag and hair dryer. It was a terrible sinking feeling. I felt my heart burst out of my chest. It was just terrible." The search yesterday concentrated in an area of ocean between the western shore of the Vineyard and tiny No Man's Island 3.5 miles away. Taking part were ships and aircraft of the US Coast Guard and the civil air patrol. Above, circled a US Air Force C-130 acting as an air traffic control centre.
But it is a small plane in a large expanse of water that may have broken into a thousand pieces. And although the sandy seabed is only about 300 feet deep - not too far for divers to venture - there are areas of large boulder fields that could shield any wreckage. And there is something else few wanted to talk about yesterday: these are waters favoured during the summer by sharks.
All the while, across just 20 miles of water at Hyannisport on Cape Cod, the Kennedy family can only wait, the world's press thronging a few yards from the compound's entrance. The weekend that had meant to be one of joy for a young couple getting married had not just been ruined, it had become a rehearsal for a labour the family knows too well - the labour of tragic loss. Most of the wedding guests were gone by yesterday, leaving behind onlymembers of the family and a billowing but empty white marquee. They were, one acquaintance said, holding themselves together. "It's a kind of stoic optimism," he said. This is a family that has been through a lot. You move forward by hope."
But hope seems forlorn. "A Fallen Son," said the front page of the Cape Cod Times. In New York there were 25 pages of JFK in the Post, 24 pages in the Daily News. Only Diana could beat him on the news stand. Now in death, his story resonates with the family tragedies that came before - in its sadness and the shock it delivers to America.