The remains of an F-16 Israeli war plane can be seen near the Israeli village of Harduf February 10, 2018. REUTERS/ Ronen Zvulun

Smoke is seen where a small airplane crashed near a supermarket in a residential area outside Lisbon, Portugal April 17, 2017. REUTERS/Rafael Marchante

Wreckage of a helicopter is seen after it crashed in Istanbul, Turkey, March 10, 2017. REUTERS/Osman Orsal

Wreckage of a helicopter is seen after it crashed in Istanbul, Turkey, March 10, 2017. REUTERS/Osman Orsal TPX IMAGES OF THE DAY

French rescue services work at the scene of an accident involving fifty vehicles which crashed due to fog on the road between La Roche-sur-Yon and Sables-d'Olonne, France, that killed five and injured more than forty, December 20, 2016. REUTERS/Stephane Mahe

A rescue worker sits near the wreckage of a plane that crashed into the Colombian jungle with Brazilian soccer team Chapecoense onboard near Medellin, Colombia, November 29, 2016 REUTERS/Jaime Saldarriaga

ATTENTION EDITORS - VISUAL COVERAGE OF SCENES OF INJURY OR DEATHRescue crew work at the wreckage of a plane that crashed into the Colombian jungle with Brazilian soccer team Chapecoense onboard near Medellin, Colombia, November 29, 2016. REUTERS/Jaime Saldarriaga TPX IMAGES OF THE DAY

An Air Force F-16 with the Thunderbirds air demonstration squadron sits crashed in a field 4 miles south of Colorado Springs after performing a fly-by of the U.S. Air Force Academy graduation ceremony where President Barack Obama gave the commencement address, in Colorado Springs, Colorado, U.S. June 2, 2016. REUTERS/John Wark

Civilians carry a piece of a Syrian warplane that was shot down in the Talat al-Iss area, south of Aleppo, Syria April 5, 2016. REUTERS/Ammar Abdullah

Boys pose with pieces of a Syrian warplane that was shot down in the Talat al-Iss area, south of Aleppo, Syria April 5, 2016. REUTERS/Ammar Abdullah

A man inspects the wreckage of a Syrian warplane that was shot down in the Talat al-Iss area, south of Aleppo, Syria April 5, 2016. REUTERS/Ammar Abdullah

Rebel fighters and civilians gather around the wreckage of a Syrian warplane that was shot down in the Talat al-Iss area, south of Aleppo, Syria April 5, 2016. REUTERS/Ammar Abdullah

Civilians inspect the wreckage of a Syrian warplane that was shot down in the Talat al-Iss area, south of Aleppo, Syria April 5, 2016. REUTERS/Ammar Abdullah

Rebel fighters and civilians gather around the wreckage of a Syrian warplane that was shot down in the Talat al-Iss area, south of Aleppo, Syria April 5, 2016. REUTERS/Ammar Abdullah

Rebel fighters and civilians gather around the wreckage of a Syrian warplane that was shot down in the Talat al-Iss area, south of Aleppo, Syria April 5, 2016. REUTERS/Ammar Abdullah TPX IMAGES OF THE DAY

A diver (C) gestures to a boat that arrived to salvage a airplane that made an emergency landing in the waters of the Mediterranean sea off the shore of Tel Aviv, Israel, April 3, 2016. REUTERS/Baz Ratner

A fisherman watches as a police boat patrols near a airplane that made an emergency landing in the waters of the Mediterranean sea off the shore of Tel Aviv, Israel, April 3, 2016. REUTERS/Baz Ratner

Policemen on a boat work near an airplane that made an emergency landing in the waters of the Mediterranean sea off the shore of Tel Aviv, Israel, April 3, 2016. REUTERS/Baz Ratner

A man takes a photo with his cell phone of an airplane that made an emergency landing in the waters of the Mediterranean sea off the shore of Tel Aviv, Israel, April 3, 2016. REUTERS/Baz Ratner

A policeman puts a cable around the tail of an airplane that made an emergency landing in the waters of the Mediterranean sea off the shore of Tel Aviv, Israel, April 3, 2016. REUTERS/Baz Ratner

A police boat patrols near a airplane that made an emergency landing in the waters of the Mediterranean sea off the shore of Tel Aviv, Israel, April 3, 2016. REUTERS/Baz Ratner

Relatives and family walk at the crash zone in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Relatives and family look at the crash zone in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Relatives and family walk at the crash zone in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

White roses lie on the ground of the crash site in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier TPX IMAGES OF THE DAY

Relatives and family look at the crash zone in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Relatives and family look at the crash zone in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Relatives and family look at the crash zone in Le Vernet during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes, France, March 24, 2016.REUTERS/Jean-Paul Pelissier

White roses lie on the ground of the crash site in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

White roses lie on the ground of the crash site in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

White roses lie on the ground of the crash site in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

White roses lie on the ground of the crash site in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

French gendarmes secure the area of the crash zone in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

French gendarmes secure the area of the crash zone in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Relatives and family look at the crash zone in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Relatives and family look at the crash zone in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Relatives and family walk at the crash zone in Le Vernet,France, March 24, 2016during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes.REUTERS/Jean-Paul Pelissier

Relatives and family walk at the crash zone in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes.REUTERS/Jean-Paul Pelissier

Relatives and family walk at the crash zone in Le Vernet,France, March 24, 2016during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes.REUTERS/Jean-Paul Pelissier

Relatives and family walk at the crash zone in Le Vernet,France, March 24, 2016during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes.REUTERS/Jean-Paul Pelissier

Relatives and family look at the crash zone in Le Vernet, France, March 24, 2016 during the first anniversary ceremony to commemorate the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Members of victim's families attend a ceremony for the first anniversary of the Germanwings crash at the memorial site in Le Vernet, France, March 24, 2016 to pay tribute to the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Members of victim's families attend a ceremony for the first anniversary of the Germanwings crash at the memorial site in Le Vernet, France, March 24, 2016 to pay tribute to the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Lufthansa Chief Executive Carsten Spohr (R) and Germanwings Managing Director Thomas Winkelmann (L) arrive at a ceremony for the first anniversary of the Germanwings crash at the memorial site in Le Vernet, France, March 24, 2016, to pay tribute to the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

General view of the memorial site for the first anniversary of the Germanwings crash in Le Vernet, France, March 24, 2016 during a ceremony to pay tribute to the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Lufthansa Chief Executive Carsten Spohr (2ndL) and Germanwings Managing Director Thomas Winkelmann (2ndR) arrive at a ceremony for the first anniversary of the Germanwings crash at the memorial site in Le Vernet, France, March 24, 2016, to pay tribute to the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Members of victim's families arrive to attend a ceremony for the first anniversary of the Germanwings crash at the memorial site in Le Vernet, France, March 24, 2016 to pay tribute to the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Members of victim's families arrive to attend a ceremony for the first anniversary of the Germanwings crash at the memorial site in Le Vernet, France, March 24, 2016 to pay tribute to the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Members of victim's families arrive to attend a ceremony for the first anniversary of the Germanwings crash at the memorial site in Le Vernet, France, March 24, 2016 to pay tribute to the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Members of victim's families arrive to attend a ceremony for the first anniversary of the Germanwings crash at the memorial site in Le Vernet, France, March 24, 2016 to pay tribute to the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Members of victim's families arrive during a ceremony for the first anniversary of the Germanwings crash at the memorial site in Le Vernet, France, March 24, 2016 to pay tribute to the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Members of victim's families arrive to attend a ceremony for the first anniversary of the Germanwings crash at the memorial site in Le Vernet, France, March 24, 2016 to pay tribute to the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Members of victim's families arrive to attend a ceremony for the first anniversary of the Germanwings crash at the memorial site in Le Vernet, France, March 24, 2016 to pay tribute to the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Lufthansa Chief Executive Carsten Spohr (R) and Germanwings Managing Director Thomas Winkelmann (L) arrive at a ceremony for the first anniversary of the Germanwings crash at the memorial site in Le Vernet, France, March 24, 2016, to pay tribute to the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Lufthansa Chief Executive Carsten Spohr (C) and Germanwings Managing Director Thomas Winkelmann (L) arrive at a ceremony for the first anniversary of the Germanwings crash at the memorial site in Le Vernet, France, March 24, 2016, to pay tribute to the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

Lufthansa Chief Executive Carsten Spohr (R) and Germanwings Managing Director Thomas Winkelmann (C) arrive at a ceremony for the first anniversary of the Germanwings crash at the memorial site in Le Vernet, France, March 24, 2016, to pay tribute to the 150 victims of the Germanwings Airbus A320 that crashed in a remote area of the French Alps near Seyne-les-Alpes. REUTERS/Jean-Paul Pelissier

People gather to commemorate the victims of the crashed Flight FZ981, a Boeing 737-800 operated by Dubai-based budget carrier Flydubai, outside the airport of Rostov-On-Don, Russia, March 20, 2016. REUTERS/Maxim Shemetov TPX IMAGES OF THE DAY

People lay flowers in memory of the victims of the crashed Boeing 737-800 Flight FZ981 operated by Dubai-based budget carrier Flydubai, outside the airport of Rostov-On-Don, Russia, March 20, 2016. The board shows the names of victims, their dates of birth and reads "We mourn." REUTERS/Maxim Shemetov

People lay flowers in memory of the victims of the crashed Boeing 737-800 Flight FZ981 operated by Dubai-based budget carrier Flydubai, outside the airport of Rostov-On-Don, Russia, March 20, 2016. REUTERS/Maxim Shemetov

A woman reacts while standing near flowers left in memory of the victims of the crashed Boeing 737-800 Flight FZ981 operated by Dubai-based budget carrier Flydubai, outside the airport of Rostov-On-Don, Russia, March 20, 2016. REUTERS/Maxim Shemetov