Rescue teams reviewed satellite imagery and mobile phone data while four aircraft scoured seas off the island of Alderney, where unidentified debris had been spotted.
However they suspended their search on Wednesday evening after finding no trace of the missing plane after nine hours of hunting.
Cardiff City's new signing and the aircraft's pilot, named on Wednesday as Briton David Ibbotson, had been missing since Monday night (local time) and rescuers said chances of finding either of them alive were slim.
Police said a decision on whether to resume the search would be taken early on Thursday.
"We're up there looking for stuff that we don't expect to find," John Fitzgerald, chief officer of the Channel Islands Air Search told Reuters. "If there was anything on the surface I think we would have found it on the first night because the weather conditions were really good."
In a chilling voice message sent to friends, which Argentina's Clarin newspaper said was authenticated by Sala's father, the player expressed concerns about the single-engine Piper Malibu he was flying in.
"I'm in the plane and it looks like it's going to fall apart," he said. "Dad, I'm really scared."
Britain's Air Accident Investigations Branch said it had opened an investigation into the disappearance of the US registered aircraft.
Air traffic controllers had guided searchers along the path it took before it disappeared from radar screens at a little more than 2,000 feet (600 metres), Fitzgerald said.
Sala joined struggling Cardiff from FC Nantes last week for a club record fee of about €17 million euros ($NZ28 million), having scored 12 goals for the French club this season.
Both clubs were fearing the worst.
Cardiff City fans laid tributes outside their stadium to a player they barely knew but had built high hopes around.
"Sala a Bluebird. R.I.P. Bro. Big Love," read one, in reference to the team's nickname.
In Nantes, supporters laid rows of yellow flowers and held club scarves aloft in the city centre late on Tuesday.
Police on Tuesday said the chance of finding survivors was slim and the prospect appeared bleaker a day later, with the water temperature in the Channel barely 10degC.
"There's no chance. You'd have to be really, really fit to survive even four or five hours in the water," Fitzgerald said.
He said the pilot had filed a 'VFR' flight plan, which requires aircraft to avoid bad weather, have sight of the ground and stay out of certain air corridors.
The plane had been cruising at 5000 feet (1525 metres) when the pilot requested to descend to a lower altitude on passing Guernsey. It lost radar contact at 2300 feet, Guernsey police said.
British media on Wednesday cited Cardiff chairman Mehmet Dalman as saying the club had not organised Sala’s travel plans. "He declined and made his own arrangements," Mehmet was quoted as saying.
