The Air Accidents Investigation Branch (Aaib), which is looking into the disappearance of the aircraft over the English Channel on 21 January, said the cushions were discovered on the Normandy coastline on 28 January
"From a preliminary examination we have concluded that it is likely that the cushions are from the missing aircraft," the Aaib said in a statement
The plane vanished from radar around 20 kilometres north of the Channel island of Guernsey. Police suspended the search for Sala and pilot Dave Ibbotson on 24 January after a three day hunt involving planes and boats failed to locate it.
The Aaib said with the help of Britain's Ministry of Defence it had commissioned a specialist survey vessel equipped with sonar equipment to scour the seabed for the plane.
"If the wreckage is found, a remotely operated vehicle will be used to visually examine the wreckage," it added.
Sala, 28, had just completed a move to the English Premier League side Cardiff City from the French team Nantes when the craft went down.
The AAIB said it had identified a search area of around four square nautical miles based on the flight path and last known radar position.
It added it was in contact with David Mearns, a shipwreck hunter hired by Sala's family. "We are liaising closely with those involved to maximise the chance of locating any wreckage and ensure a safe search operation," the Aaib said.