Emiliano Sala, the Argentinian footballer who signed for Cardiff City on Saturday, was on a private plane that disappeared near the Channel Islands on Monday evening, prompting an extensive search and rescue operation that was suspended at 5pm on Tuesday, with Guernsey police admitting that the chances of survival are “slim”.

The 28-year-old had been travelling from Nantes to Cardiff, after returning to France at the weekend to say goodbye to his former teammates. The French civil aviation authority confirmed that Sala was one of two people on board the small plane – a Piper Malibu – that set off from Nantes at 7.15pm and went missing near the Casquets lighthouse little more than a hour later. There is still no explanation for why the light aircraft disappeared off the radar.

Ken Choo, Cardiff’s chief executive officer, said that everybody at the Premier League club was “having an emotional crisis” about the situation and that they were praying for good news. It was hard, however, to be optimistic about the prospects of the search and rescue services finding Sala and the pilot alive after Guernsey police’s final update on Tuesday. “We have found no signs of those on board,” they said. “If they did land on the water, the chances of survival are at this stage, unfortunately, slim.”

By that point the search operation, which started on Monday evening and involved planes, helicopters and lifeboats, had covered 1155sq miles across a 15-hour period. “A number of floating objects have been seen in the water,” police said. “We have been unable to confirm whether any of these are from the missing aircraft.”

John Fitzgerald, the Channel Islands air search chief officer, told the Associated Press: “After all this time the weather’s quite cold, the water is very cold out there … I am not expecting anyone to be alive. I don’t think the coastguard are either. We just don’t know how it disappeared at the end of [Monday].”

The news that the plane had gone missing with Sala on board was greeted with a sense of despair and dismay by staff, players and supporters at Cardiff and Nantes. Sala, who joined Cardiff for a club-record £15m fee after scoring 42 goals for Nantes, had been due to train with the Welsh club for the first time on Tuesday morning.

Play Video 0:52 Emiliano Sala was 'so ready' to join us, says Cardiff City chief executive – video

“We were very shocked upon hearing the news that the plane had gone missing,” Choo said in a statement on Cardiff’s website. “We expected Emiliano to arrive last night into Cardiff and today was due to be his first day with the team. Our owner, Tan Sri Vincent Tan, and chairman, Mehmet Dalman, are all very distressed about the situation. We made the decision first thing this morning to call off training with the thoughts of the squad, management staff and the entire club with Emiliano and the pilot.”

Choo was with Sala in Cardiff when the transfer was sealed and said the player had described the move as “one of the best days in his life”. Choo added: “You could see from the face he was so happy to be here and so ready to start … We really feel sad to hear of this news because we have met such a great person.”

Facebook Twitter Pinterest The Alderney lifeboat returns to the island for a crew change before resuming the search for the missing plane. Photograph: Declan Gaudion/RNLI/EPA

Nantes’ president, Waldemar Kita, said: “I’ll always have hope, he’s a fighter. It’s not over, maybe he’s somewhere.” The club was said to be in a “state of shock”. Nantes cancelled training on Tuesday and their Coupe de France match against Entente Sannois Saint Gratien, due to be played on Wednesday, was postponed.

Although it will be some time before the authorities can ascertain exactly what happened with the plane, some details have been released. Police said the aircraft had requested descent on passing Guernsey but that Jersey air traffic control lost contact with it when the plane was at 2,300ft. Guernsey Coastguard confirmed that it received an alert at 8.23pm on Monday that a light aircraft had gone missing and said that searches were carried out until 2am, at which point conditions forced a halt. The search resumed at 8am the following day.

Although Sala played youth football in Argentina, he spent his whole senior career in France. He joined Bordeaux in 2012 and went on loan to three clubs before signing for Nantes in 2015, where he was a hugely popular figure as well as a prolific goalscorer. “He was the spirit of football,” said Thomas Renault, who played alongside Sala for US Orléans. “The kind of professional player who never gives up, who works. Everyone said the same wherever he went.”