Five aircraft and two lifeboats resumed searches on Wednesday.
Reports in France claimed Sala had told Nicolas Pallois, a team-mate who drove him to the airport, that the trip “had been bumpy and he feared his safety for the journey back”.
The Cardiff City chief executive Ken Choo said everyone at the club was “very distressed” and “praying for positive news,” while, speaking from Argentina, Sala’s father Horacio said he was “desperate” for news.
He broke down in tears as he described him as a “small town humble boy”, adding: “I just can’t believe it.” Sala’s mother, Mercedes Taffarel, said her son was “enjoying the best moment of his career so far.”
Meanwhile, leading sports lawyers told The Telegraph the financial situation could become complex for Cardiff and Nantes in the weeks ahead.