Vapour trails from a Swissair plane are seen in the sky over the ski resort of Val d'Isere, France, December 1, 2016. REUTERS/Christian Hartmann

An Airbus A340 aircraft of Swissair takes off from the runway in front of the expulsion prison next to Zurich airport in Kloten in the Canton of Zurich, Switzerland June 13, 2015. Picture taken June 13. REUTERS/Arnd Wiegmann

A Swiss International aircraft flies past the HSBC headquarters building in the Canary Wharf financial district in east London February 15, 2015. HSBC apologised to customers and investors on Sunday for past practices at its Swiss private bank after allegations that it helped hundreds of clients to dodge taxes. REUTERS/Peter Nicholls (BRITAIN - Tags: BUSINESS CRIME LAW TRANSPORT TPX IMAGES OF THE DAY)

Members of the Swiss aerobatic team Patrouille Swiss fly in formation with a Swiss Airbus A 320 over the men's Alpine Skiing World Cup downhill in Wengen January 18, 2015. REUTERS/Denis Balibouse (SWITZERLAND - Tags: SPORT SKIING TRANSPORT)

Members of the Swiss aerobatic team Patrouille Swiss fly in formation with a Swiss Airbus A 320 over the men's Alpine Skiing World Cup Super Combined in Wengen January 16, 2015. REUTERS/Ruben Sprich (SWITZERLAND - Tags: SPORT SKIING TRANSPORT TPX IMAGES OF THE DAY)

A Swiss aircraft is seen at Cointrin airport on the border with France (front) and Switzerland in Ferney Voltaire near Geneva April 28, 2014. Switzerland will vote on November 30 on an initiative from the group Ecopop which proposes a cap on the number of immigrants. The group says it is motivated by concerns about a lack of living space exerting too much pressure on the land and natural resources, rather than by opposition to foreigners. It proposes limiting immigration to just 0.2 percent of the resident population, equivalent to 16,000 people per year. This would represent a cut of more than 75 percent in annual net immigration from current levels. In Switzerland's system of direct democracy, any voter can trigger a referendum by collecting 100,000 signatures within 18 months. Picture taken April 28, 2014. REUTERS/Denis Balibouse (FRANCE - Tags: TRANSPORT BUSINESS LOGO SOCIETY IMMIGRATION TPX IMAGES OF THE DAY ELECTIONS POLITICS)

ATTENTION EDITORS: PICTURE 21 26 FOR WIDER IMAGE PACKAGE 'ALL ALONG BORDER'
TO FIND ALL SEARCH 'BALIBOUSE BORDER'

A British Airways jet approaches Heathrow Airport past a Swissair jet on the tarmac in London November 25, 2012. REUTERS/Neil Hall (BRITAIN - Tags: TRANSPORT BUSINESS)

A Swiss airline plane prepares to land at Cointrin airport in Geneva March 20, 2012. The International Air Transport Association (IATA) will release its updated industry financial forecast on March 20, 2012. REUTERS/Denis Balibouse (SWITZERLAND - Tags: TRANSPORT BUSINESS)

An ashtray with a scale model of a Swissair plane and other items of the former Swiss airline are offered during a sale at Zurich airport September 29, 2011. On October 2, 2001 Switzerland's flag carrier ceased all operations after its banks pulled the plug on the cash-strapped airline. REUTERS/Arnd Wiegmann (SWITZERLAND - Tags: BUSINESS TRANSPORT)

An ashtray with a scale model of a Swissair plane and other items of the former Swiss airline are offered during a sale at Zurich airport September 29, 2011. On October 2, 2001 Switzerland's flag carrier ceased all operations after its banks pulled the plug on the cash-strapped airline. REUTERS/Arnd Wiegmann (SWITZERLAND - Tags: BUSINESS TRANSPORT)

Trolleys, bags and other items of the former Swissair airline are offered during a sale at Zurich airport September 29, 2011. On October 2, 2001 Switzerland's flag carrier ceased all operations after its banks pulled the plug on the cash-strapped airline. REUTERS/Arnd Wiegmann (SWITZERLAND - Tags: BUSINESS TRANSPORT)

An ashtray with a scale model of a Swissair plane and other items of the former Swiss airline are offered during a sale at Zurich airport September 29, 2011. On October 2, 2001 Switzerland's flag carrier ceased all operations after its banks pulled the plug on the cash-strapped airline. REUTERS/Arnd Wiegmann (SWITZERLAND - Tags: BUSINESS TRANSPORT)

Cows graze in a field in front of a Swiss International Airlines plane parked on the tarmac at Zurich airport in Kloten April 18, 2010. Switzerland's airports remain closed over the weekend due to the ash cloud caused by an Icelandic volcano that turned northern Europe into a no-fly zone. REUTERS/Christian Hartmann (SWITZERLAND - Tags: TRANSPORT ANIMALS ENVIRONMENT BUSINESS)

A Swiss airlines employee removes the snow from a plane after the first snow falls at Zurich airport in Kloten October 30, 2008. REUTERS/Christian Hartmann (SWITZERLAND)

An aircraft of Swiss flag carrier Swissair takes off at Zurich airport October 20, 2008. REUTERS/Arnd Wiegmann (SWITZERLAND)

Aircraft of Swiss flag carrier Swissair stand at Zurich airport October 20, 2008. REUTERS/Arnd Wiegmann (SWITZERLAND)

Aircraft of Swiss flag carrier Swissair stand at Zurich airport October 20, 2008. REUTERS/Arnd Wiegmann (SWITZERLAND)

An aircraft of Swiss flag carrier Swissair stands at Zurich airport October 20, 2008. REUTERS/Arnd Wiegmann (SWITZERLAND)

Aircraft of Swiss flag carrier Swissair stand at Zurich airport October 20, 2008. REUTERS/Arnd Wiegmann (SWITZERLAND)

An aircraft of Swiss flag carrier Swissair taxis to take off at Zurich airport October 20, 2008. REUTERS/Arnd Wiegmann (SWITZERLAND)

Flowers are placed during the 10th anniversary memorial service for the Swissair Flight 111 crash in Bayswater, Nova Scotia, September 2, 2008. All 229 people onboard the MD-11 aircraft perished after the aircraft crashed in the ocean near the memorial site. REUTERS/Paul Darrow (CANADA)

A harp is played during the 10th anniversary memorial service for the Swissair Flight 111 air crash in Bayswater, Nova Scotia, September 2, 2008. All 229 people onboard the MD-11 aircraft perished after the aircraft crashed in the ocean near the memorial site. REUTERS/Paul Darrow (CANADA)

Family members of the Swissair Flight 111 air crash grieve during the 10th anniversary memorial service at Bayswater, Nova Scotia, September 2, 2008. Swissair Flight 111 crashed into the sea off Nova Scotia on September 2, 1998, claiming the lives of all 229 people on board. REUTERS/Paul Darrow (CANADA)

Veronique Noceto of France looks out to the sea during the 10th anniversary service at the Swissair Flight 111 memorial in Bayswater, Nova Scotia, September 2, 2008. Swissair Flight 111 crashed into the sea off Nova Scotia on September 2, 1998, claiming the lives of all 229 people on board, including Noceto's parents. REUTERS/Paul Darrow (CANADA)

Veronique Noceto of France hugs her five-year-old daughter Kaitlyn during the 10th anniversary service at the Swissair Flight 111 memorial in Bayswater, Nova Scotia, September 2, 2008. Swissair Flight 111 crashed into the sea off Nova Scotia on September 2, 1998, claiming the lives of all 229 people on board, including Noceto's parents. REUTERS/Paul Darrow (CANADA)

Veronique Noceto of France shows the names of her parents on the Swissair Flight 111 memorial to her five-year-old daughter Kaitlyn during the 10th anniversary service in Bayswater, Nova Scotia, September 2, 2008. Swissair Flight 111 crashed into the sea off Nova Scotia on September 2, 1998, claiming the lives of all 229 people on board, including Noceto's parents. REUTERS/Paul Darrow (CANADA)

Family members and friends of victims of the Swissair Flight 111 air crash console each other after the 10th anniversary memorial service at Bayswater, Nova Scotia, September 2, 2008. Swissair Flight 111 crashed into the sea off Nova Scotia on September 2, 1998, claiming the lives of all 229 people on board. REUTERS/Paul Darrow (CANADA)

Monica Danon (L) of Geneva, who lost her husband in the air crash, and John Butt (R), who served as the chief medical examiner for the crash, pay their respects at the Swissair Flight 111 memorial during the 10th anniversary service in Bayswater, Nova Scotia, September 2, 2008. Swissair Flight 111 crashed into the sea off Nova Scotia on September 2, 1998, claiming the lives of 229 people. REUTERS/Paul Darrow (CANADA)

A couple embrace at the Swissair Flight 111 Memorial in Peggy's Cove, Nova Scotia, September 1, 2008. 229 people perished after Flight 111 crashed off the coast of Nova Scotia on September 2, 1998. REUTERS/Paul Darrow (CANADA)

David Danon (L) of Geneva embraces family friend Bruno Morin of New York at the Swissair Flight 111 Memorial in Peggy's Cove, Nova Scotia September 1, 2008. Danon's father was one of the 229 people who perished after Flight 111 crashed off the coast of Nova Scotia on September 2, 1998. REUTERS/Paul Darrow (CANADA)

Monica Danon (L-R) of Geneva embraces family friend Bruno Morin of New York and her son David at the Swissair Flight 111 Memorial in Peggy's Cove, Nova Scotia September 1, 2008. Her husband was one of the 229 people who perished after Flight 111 crashed off the coast of Nova Scotia on September 2, 1998. REUTERS/Paul Darrow (CANADA)

David Danon of Geneva looks over the Swissair Flight 111 Memorial in Peggy's Cove, Nova Scotia, September 1, 2008. His father was one of the 229 people who perished after Flight 111 crashed off the coast of Nova Scotia on September 2, 1998. REUTERS/Paul Darrow (CANADA)

Stuffed animals and flowers are placed at the Swissair Flight 111 Memorial in Peggy's Cove, Nova Scotia, September 1, 2008. 229 people perished after Flight 111 crashed off the coast of Nova Scotia on September 2, 1998. REUTERS/Paul Darrow (CANADA)

A Swiss flag is placed at the Swissair Flight 111 Memorial in Peggy's Cove, Nova Scotia, September 1, 2008. 229 people perished after Flight 111 crashed off the coast of Nova Scotia on September 2, 1998. REUTERS/Paul Darrow (CANADA)

State attorney Christian Weber looks on during a media conference after the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

State attorney Christian Weber adjust his hair during a media conference after the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Paul Ramer, lawyer of former Swissair Chief Executive Mario Corti, talks to a journalist after the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair Chief Executive Eric Honegger (L) signs a panel which reads 'Swissair' after the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair Chief Executive Eric Honegger (L) answers questions to the media after the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

National Councillors discuss next to a TV set during a special broadcast on the verdict of the Swissair trial in the national council during the council's summer session in Bern June 7, 2007. REUTERS/Pascal Lauener (SWITZERLAND)

National Councillor Susanne Leutenegger Oberholzer (R) and a National Usher (L) look at a special TV programme on the verdict of the Swissair trial in the national council during the council's summer session in Bern June 7, 2007. REUTERS/Pascal Lauener (SWITZERLAND)

National Councillor Susanne Leutenegger Oberholzer adjusts a TV set before a special broadcast on the verdict of the Swissair trial in the national council during the council's summer session in Bern June 7, 2007. REUTERS/Pascal Lauener (SWITZERLAND)

State attorney Hanspeter Hirt arrives for the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

State attorney Christian Weber arrives for the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair administrative board member Thomas Schmidheiny and his lawyer Nathan Landshut arrive for the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair administrative board member Vreni Spoerry (L) and her lawyer Peter Bettoni arrive for the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair administrative board member Vreni Spoerry arrives for the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair administrative board member Vreni Spoerry arrives for the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair administrative board member Lukas Muehlemann (R) and his lawyer Bernhard Gehrig arrive for the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair Chief Executive Eric Honegger arrives for the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair administrative board member Thomas Schmidheiny arrives for the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair administrative board member Thomas Schmidheiny arrives for the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Paul Ramer, lawyer of former Swissair Chief Executive Mario Corti, arrives for the verdict of the Swissair trial in Buelach near Zurich, June 7, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair CFO Jacqualyn Fouse (L) and Chief Executive Mario Corti (C) speak to the media after Corti's defence at the Swissair trial in Buelach near Zurich, March 6, 2007. Switzerland's biggest ever economic crime trial started in Zurich on January 16, 2007 when a district court prepared to hear evidence against 19 former managers, board members and consultants of failed airline Swissair. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair Chief Executive Mario Corti speaks to the media after his defence at the Swissair trial in Buelach near Zurich, March 6, 2007. Switzerland's biggest ever economic crime trial started in Zurich on January 16, 2007 when a district court prepared to hear evidence against 19 former managers, board members and consultants of failed airline Swissair. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair Chief Executive Mario Corti (L) speaks to the media after his defence at the Swissair trial in Buelach near Zurich, March 6, 2007. Switzerland's biggest ever economic crime trial started in Zurich on January 16, 2007 when a district court prepared to hear evidence against 19 former managers, board members and consultants of failed airline Swissair. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair Chief Executive Mario Corti (R) speaks to the media after his defense at the Swissair trial in Buelach near Zurich March 6, 2007. Switzerland's biggest ever economic crime trial started in Zurich on January 16, 2007 when a district court prepared to hear evidence against 19 former managers, board members and consultants of failed airline Swissair. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair Chief Executive Mario Corti (L) speaks to the media after his defense at the Swissair trial in Buelach near Zurich, March 6, 2007. Switzerland's biggest ever economic crime trial started in Zurich on January 16, 2007 when a district court prepared to hear evidence against 19 former managers, board members and consultants of failed airline Swissair. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair Chief Executive Mario Corti (R) speaks to the media after his defense at the Swissair trial in Buelach near Zurich March 6, 2007. Switzerland's biggest ever economic crime trial started in Zurich on January 16, 2007 when a district court prepared to hear evidence against 19 former managers, board members and consultants of failed airline Swissair. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)

Former Swissair Chief Executive Mario Corti (L) and his lawyer Paul Ramer leave for a break during the Swissair trial in Buelach near Zurich, March 6, 2007. SAirGroup, Swissair's parent company, collapsed in 2001 with debts of around 17 billion Swiss francs ($13.64 billion), following a disastrous acquisition campaign that targeted struggling European rivals. REUTERS/Sebastian Derungs (SWITZERLAND)