Sala is missing after his plane from Nantes to Cardiff disappeared yesterday evening.
Search and rescue are trying to locate the aircraft and Cardiff and Nantes are waiting for news.
French police have confirmed Sala was on the Piper Malibu plane that departed Nantes for Wales last night.
And French news outlet 20 Minutes Nantes have revealed Sala was cornered about the plane.
According to David Phelippeau’s report, Sala had arrived in Nantes on the same plane from Cardiff over the weekend.
On Monday he arrived at the club to say goodbye to his team-mates and have lunch with them one last time.
Sala is said to have given a speech before his departure.
He then returned to the airport with his team-mate Nicolas Pallois, and expressed his ‘fears about the safety of the flight’.
Cardiff paid a club-record £15m to sign Sala this month and he was expected to play against Arsenal next Tuesday.
HM Coastguard said the incident was not in the UK search and rescue area, but had sent two helicopters to help.
“HM Coastguard are currently assisting Guernsey Coastguard with a search for a light aircraft off Alderney in the Channel Islands,” a spokeswoman said.
“HM Coastguard helicopters from Solent and Newquay have been helping to search overnight with nothing found.”
Sala was due to arrive at the Vale of Glamorgan Hotel in Hensol, South Wales today.
The 28-year-old started his career at Bordeaux and joined Nantes in 2015 after a short loan stint at Caen.
He had scored 13 goals in 21 appearances for Nantes this season, triggering Cardiff’s interest.