Search and rescue operations will resume Wednesday morning, police said.
Sala, 28, had just signed with English Premier League club Cardiff City for a reported £15 million ($19.3 million) from French club Nantes. The striker was returning to his new club after saying farewell to his former teammates in France.
The plane, a single turbine Piper Malibu, was flying to Cardiff from Nantes in northern France when it disappeared from radar near the Channel Islands just before 8:30 p.m. local time (3:30 p.m. ET) Monday.
Sala’s name was on the list of passengers, Frederic Solano of France’s Directorate General for Civil Aviation told CNN.
Authorities, who have searched 1,155 square miles, said that floating objects had been spotted in the water, but they weren’t able to confirm whether they were from the missing aircraft.
“We have found no signs of those on board. If they did land on the water, the chances of survival are at this stage, unfortunately, slim,” Guernsey police said on Twitter.
The plane requested descent on passing Guernsey but lost contact with air traffic control while it was flying at 2,300 feet.
“There was no distress call, it was simply lost from radar and from communications,” Capt. David Barker, harbormaster for the state of Guernsey, told reporters.
“The weather conditions are better now, but the seawater is not very warm. I’m imagining that people in a light aircraft wouldn’t be wearing particularly warm clothing, and so it is concerning because if they’re in the water, their chances of surviving are diminishing all the time.”
‘I was in shock’
Sala’s father, Horacio, told CNN en Español that he heard the news early Tuesday.
“I was in shock,” he said, adding that he had not received contact from the authorities or his son’s soccer club.
He last spoke with his son Sunday after he signed with Cardiff City.
“He was happy for his next step … going forward … a bigger club and he could play premierships … he was very pleased,” Horacio Sala said.
Cardiff City, which paid a club record fee for Sala, said Tuesday it would “continue to pray for positive news.”
“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.
“All of us at Cardiff City FC would like to thank our fans, and the entire footballing family for their support at this difficult time. We continue to pray for positive news.”
Sala, who agreed a three-year deal with the Welsh club Saturday, had scored 12 league goals for Nantes this season. Cardiff is in the Premier League’s relegation zone and has scored just 19 goals in 23 league games.
The Argentine athlete would have likely been available to make his debut for Cardiff in next week’s Premier League match at Arsenal.
Sala scored 42 goals for Nantes since joining from Bordeaux in 2015. Only two players have scored more goals than Sala in France’s top flight this season — Kylian Mbappe and Nicolas Pepe.
In his most recent tweet Monday, just before he was due to fly, Sala posted a photo of himself with the Nantes FC team and the caption: “the last one, goodbye.”
“It is not over, he might still be somewhere. Waiting for news we hope to be positive, we are very touched by all the support we have received since this morning.”
France’s Football Federation confirmed on its website it had postponed Nantes’ French Cup game scheduled for Wednesday.
CNN’s Vasco Cotovio and Martin Goillandeau contributed to this report.