The entrance of an aerodrome gun tower is surrounded by wild flowers and grass in Kaohsiung, Taiwan, January 1, 2020. REUTERS/Ann Wang SEARCH "TAIWAN BUNKER" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

French inventor Franky Zapata lands on a Flyboard during a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata is seen on a Flyboard next to his wife after landing during a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata on a Flyboard is helped by his wife to install a fuel supply bag on his back during a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata flies on a Flyboard during a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol TPX IMAGES OF THE DAY

French inventor Franky Zapata flies on a Flyboard during a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata poses with a a Flyboard during a news conference as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata is seen with a Flyboard before a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata flies on a Flyboard during a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata checks a Flyboard before a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata is seen with a Flyboard during a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata attends a news conference with his wife and his son after a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata flies on a Flyboard during a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata flies on a Flyboard during a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata flies on a Flyboard during a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata flies on a Flyboard during a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata poses with a Flyboard before a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata poses with a Flyboard before a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

French inventor Franky Zapata poses with a Flyboard before a demonstration as he prepares to cross the English channel from Sangatte in France to Dover, at the Saint-Inglevert aerodrome near Calais, France, July 24, 2019. REUTERS/Pascal Rossignol

Former soldier Ash Hall, who lost his legs in Afghanistan, drives the Team BRIT racing simulator at Dunsfold Aerodrome, Britain February 27, 2019. Picture taken February 27, 2019. REUTERS/Alan Baldwin

Nicolas Hamilton, brother of Formula One champion Lewis, poses with a Team BRIT Aston Martin at Dunsfold Aerodrome, Britain, February 27, 2019. Picture taken February 27, 2019. REUTERS/Alan Baldwin

Track manager Gordon Sweeney points to old photographs showing the Mallala Motor Sport Track being used as an aerodrome during World War II, located on the outskirts of the town of Mallala, north of Adelaide, South Australia, August 22, 2018. Picture taken August 22, 2018. REUTERS/David Gray

Battle of Britain aircraft fly during a display at Goodwood Aerodrome in West Sussex, England, Tuesday, September 15, 2015. Britain's Prince Harry joined Battle of Britain veterans and wounded servicemen supported by his Endeavour Fund in a historic flypast to mark the 75th Anniversary of victory in the Battle of Britain. REUTERS/Kirsty Wigglesworth/Pool

Battle of Britain aircraft fly during a display at Goodwood Aerodrome in West Sussex, England, Tuesday, September 15, 2015. Britain's Prince Harry joined Battle of Britain veterans and wounded servicemen supported by his Endeavour Fund in a historic flypast to mark the 75th Anniversary of victory in the Battle of Britain. REUTERS/Kirsty Wigglesworth/Pool

Britain's Prince Harry chats with a pilot and veteran Tom Neill, after Neill was flown in a Spitfire during a Battle of Britain display at Goodwood Aerodrome in West Sussex, England, September 15, 2015. Prince Harry joined Battle of Britain veterans and wounded servicemen supported by his Endeavour Fund in a flypast to mark the 75th Anniversary of victory in the Battle of Britain. REUTERS/Kirsty Wigglesworth/Pool

Britain's Prince Harry (2nd R), poses for a photograph with pilots and veteran Tom Neill (C), after Neill was flown in a Spitfire during a Battle of Britain display at Goodwood Aerodrome in West Sussex, England, September 15, 2015. Prince Harry joined Battle of Britain veterans and wounded servicemen supported by his Endeavour Fund in a flypast to mark the 75th Anniversary of victory in the Battle of Britain. REUTERS/Kirsty Wigglesworth/Pool

Britain's Prince Harry (R) jokes arounds with pilots after they took part in a Battle of Britain display at Goodwood Aerodrome in West Sussex, England, September 15, 2015. Prince Harry joined Battle of Britain veterans and wounded servicemen supported by his Endeavour Fund as they took part in a flypast to mark the 75th Anniversary of victory in the Battle of Britain. REUTERS/Kirsty Wigglesworth/Pool

Britain's Prince Harry (2nd R), poses for a photograph with pilots and veteran Tom Neill (C), after Neill was flown in a Spitfire during a Battle of Britain display at Goodwood Aerodrome in West Sussex, England, September 15, 2015. Prince Harry joined Battle of Britain veterans and wounded servicemen supported by his Endeavour Fund in a flypast to mark the 75th Anniversary of victory in the Battle of Britain. REUTERS/Kirsty Wigglesworth/Pool

Britain's Prince Harry (R), poses for a photograph with veteran Tom Neill after he flew in a Spitfire during a Battle of Britain display at Goodwood Aerodrome in West Sussex, England, September 15, 2015. Prince Harry gave up his seat for Tom Neill after the aircraft he was due to fly in developed a fault. Battle of Britain veterans and wounded servicemen supported by Prince Harry's Endeavour Fund took part in a flypast to mark the 75th Anniversary of victory in the Battle of Britain. REUTERS/Kirsty Wigglesworth/Pool

Britain's Prince Harry walks at Goodwood Aerodrome in West Sussex, England September 15, 2015. REUTERS/Kirsty Wigglesworth/Pool

Britain's Prince Harry walks at Goodwood Aerodrome in West Sussex, England September 15, 2015. REUTERS/Kirsty Wigglesworth/Pool

Britain's Prince Harry (R) walks with Matt Jones, Director of Boultbee Flight Academy, past Battle of Britain aircraft at Goodwood Aerodrome in West Sussex, England September 15, 2015. REUTERS/Kirsty Wigglesworth/Pool

Britain's Prince Harry walks at Goodwood Aerodrome in West Sussex, England September 15, 2015. REUTERS/Kirsty Wigglesworth/Pool

Britain's Prince Harry (2nd L) walks with Matt Jones (L), Director of Boultbee Flight Academy, Corporal Alan Robinson (2nd R) and Nathan Forster past Battle of Britain aircraft at Goodwood Aerodrome in West Sussex, England, September 15, 2015. REUTERS/Photo/Kirsty Wigglesworth/Pool

Britain's Prince Harry (R) walks with Matt Jones, Director of Boultbee Flight Academy, past Battle of Britain aircraft at Goodwood Aerodrome in West Sussex, England September 15, 2015. REUTERS/Kirsty Wigglesworth/Pool

Britain's Prince Harry (R) walks with Nathan Forster (C) and Corporal Alan Robinson, Endeavor Fund Scholars, past Battle of Britain aircraft at Goodwood Aerodrome in West Sussex, England, September 15, 2015. REUTERS/Kirsty Wigglesworth/Pool

Britain's Prince Harry (L) walks with Matt Jones, Director of Boultbee Flight Academy, past Battle of Britain aircraft at Goodwood Aerodrome in West Sussex, England, September 15, 2015. REUTERS/Kirsty Wigglesworth/Pool

A general view of the glider airfield at the aerodrome in Sisteron, in the French Alps, March 27, 2015. REUTERS/Jean-Paul Pelissier

A glider is seen on the grass airfield at the aerodrome in Sisteron, in the French Alps, March 27,2015. REUTERS/Jean-Paul Pelissier

Gliders are seen on the grass airfield at the aerodrome in Sisteron, in the French Alps, March 27,2015. REUTERS/Jean-Paul Pelissier

The U.S.-made C-130J Hercules aircraft of Indian Air Force (IAF) taxis after landing at an airstrip at the Juhu Aerodrome in Mumbai March 24, 2015. The brief landing carried out by the Indian Air Force was part of a terror preparedness exercise, according to local media reports. REUTERS/Shailesh Andrade

A man take a picture of a Cessna 208 Caravan 1 seaplane before it departs off from Juhu Aerodrome in Mumbai August 25, 2014. According to a media release, Mumbai's first leg of the commercial seaplane service connects the city to Pawna Dam, a water body near Lonavala, a popular tourist destination. REUTERS/Shailesh Andrade (INDIA - Tags: TRANSPORT)

A Cessna 208 Caravan seaplane taxis on a runway before taking off from Juhu Aerodrome in Mumbai August 25, 2014. According to a media release, Mumbai's first leg of the commercial seaplane service connects the city to Pawna Dam, a water body near Lonavala, a popular tourist destination. REUTERS/Shailesh Andrade (INDIA - Tags: TRANSPORT)

A logo of the Japan Aerospace Exploration Agency (JAXA) is seen through a viewfinder of a television camera in front of the JAXA Chofu Aerospace Center Aerodrome Branch in Tokyo January 22, 2013. Japan's transport ministry said on Tuesday that the JAXA will check the damaged battery from an All Nippon Airways Dreamliner jet that made an emergency landing in western Japan last week. The ministry said JAXA will conduct a CT-scan on the battery, which was made by Japan's GS Yuasa Corp, because the agency has the equipment to carry out the inspection. REUTERS/Issei Kato (JAPAN - Tags: TRANSPORT DISASTER BUSINESS LOGO)

A logo of Japan Aerospace Exploration Agency (JAXA) is seen in front of a gate at the JAXA Chofu Aerospace Center Aerodrome Branch in Tokyo January 22, 2013. Japan's transport ministry said on Tuesday that the JAXA will check the damaged battery from an All Nippon Airways Dreamliner jet that made an emergency landing in western Japan last week. The ministry said JAXA will conduct a CT-scan on the battery, which was made by Japan's GS Yuasa Corp, because the agency has the equipment to carry out the inspection. REUTERS/Issei Kato (JAPAN - Tags: TRANSPORT DISASTER BUSINESS LOGO)

A Jaguar badge is seen on the rear of of a vintage E Type car at BAE systems Warton aerodrome near Preston, northern England September 7, 2012. Over 40 vintage Jaguar cars are taking part in a seven day rally to mark the company's 90th anniversary. REUTERS/Phil Noble (BRITAIN - Tags: ANNIVERSARY TRANSPORT)

A Jaguar badge and leaping cat emblem are seen on the bonnet of a vintage Jaguar car at BAE systems Warton aerodrome near Preston, northern England September 7, 2012. Over 40 vintage Jaguar cars are taking part in a seven day rally to mark the company's 90th anniversary. REUTERS/Phil Noble (BRITAIN - Tags: ANNIVERSARY TRANSPORT)

A Jaguar badge and leaping cat emblem are seen on the bonnet of a vintage Jaguar car at BAE systems Warton aerodrome near Preston, northern England September 7, 2012. Over 40 vintage Jaguar cars are taking part in a seven day rally to mark the company's 90th anniversary. REUTERS/Phil Noble (BRITAIN - Tags: ANNIVERSARY TRANSPORT)

A Jaguar badge and leaping cat emblem are seen on the bonnet of a vintage Jaguar car at BAE systems Warton aerodrome near Preston, northern England September 7, 2012. Over 40 vintage Jaguar cars are taking part in a seven day rally to mark the company's 90th anniversary. REUTERS/Phil Noble (BRITAIN - Tags: ANNIVERSARY TRANSPORT)

A damaged L-410 plane is seen in a field near Borodyanka aerodrome, about 50 km (30 miles) north-west of Kiev June 10, 2012. Five people were killed and 13 others injured in Ukraine on Sunday when a storm forced an aircraft carrying parachutists to make an emergency landing, the emergencies ministry said. REUTERS/Anatolii Stepanov (UKRAINE - Tags: DISASTER TRANSPORT)

A damaged L-410 plane is seen in a field near Borodyanka aerodrome, about 50 km (30 miles) north-west of Kiev June 10, 2012. Five people were killed and 13 others injured in Ukraine on Sunday when a storm forced an aircraft carrying parachutists to make an emergency landing, the emergencies ministry said. REUTERS/Anatolii Stepanov (UKRAINE - Tags: DISASTER TRANSPORT)

Parts of a damaged L-410 plane are seen in a field near Borodyanka aerodrome, about 50 km (30 miles) north-west of Kiev June 10, 2012. Five people were killed and 13 others injured in Ukraine on Sunday when a storm forced an aircraft carrying parachutists to make an emergency landing, the emergencies ministry said. REUTERS/Anatolii Stepanov (UKRAINE - Tags: DISASTER TRANSPORT)

A damaged L-410 plane is seen in a field near Borodyanka aerodrome, about 50 km (30 miles) north-west of Kiev June 10, 2012. Five people were killed and 13 others injured in Ukraine on Sunday when a storm forced an aircraft carrying parachutists to make an emergency landing, the emergencies ministry said. REUTERS/Anatolii Stepanov (UKRAINE - Tags: DISASTER TRANSPORT)

Specialists work at the site of a crashed L-410 plane in a field near Borodyanka aerodrome, about 50 km (30 miles) north-west of Kiev June 10, 2012. Five people were killed and 13 others injured in Ukraine on Sunday when a storm forced an aircraft carrying parachutists to make an emergency landing, the emergencies ministry said. REUTERS/Anatolii Stepanov (UKRAINE - Tags: DISASTER TRANSPORT)

Specialists work in front of a crashed L-410 plane in a field near Borodyanka aerodrome, about 50 km (30 miles) north-west of Kiev June 10, 2012. Five people were killed and 13 others injured in Ukraine on Sunday when a storm forced an aircraft carrying parachutists to make an emergency landing, the emergencies ministry said. REUTERS/Anatolii Stepanov (UKRAINE - Tags: DISASTER TRANSPORT)

Vehicles from a fire department are seen near the damaged L-410 plane in a field near Borodyanka aerodrome, about 50 km (30 miles) north-west of Kiev June 10, 2012. Five people were killed and 13 others injured in Ukraine on Sunday when a storm forced an aircraft carrying parachutists to make an emergency landing, the emergencies ministry said. REUTERS/Anatolii Stepanov (UKRAINE - Tags: DISASTER TRANSPORT)

The remains of a plane that crashed in 2010, killing Poland's former president, Lech Kaczynski, and 95 others, is shown to the media at a military aerodrome near the Russian city of Smolensk April 10, 2012. Kaczynski, his wife Maria, and a sizeable chunk of Poland's military and political elite died on April 10, 2010, when their plane crashed in thick fog while trying to land at Smolensk in western Russia. REUTERS/Vasily Fedosenko (RUSSIA - Tags: ANNIVERSARY DISASTER POLITICS MILITARY)

The remains of a plane that crashed in 2010, killing Poland's former president, Lech Kaczynski, and 95 others, is shown to the media at a military aerodrome near the Russian city of Smolensk, April 10, 2012. Kaczynski, his wife Maria, and a sizeable chunk of Poland's military and political elite died on April 10, 2010, when their plane crashed in thick fog while trying to land at Smolensk in western Russia. REUTERS/Vasily Fedosenko (RUSSIA - Tags: ANNIVERSARY DISASTER POLITICS)

The remains of a plane that crashed in 2010, killing Poland's former president, Lech Kaczynski, and 95 others, is shown to the media at a military aerodrome near the Russian city of Smolensk April 10, 2012. Kaczynski, his wife Maria, and a sizeable chunk of Poland's military and political elite died on April 10, 2010, when their plane crashed in thick fog while trying to land at Smolensk in western Russia. REUTERS/Vasily Fedosenko (RUSSIA - Tags: ANNIVERSARY DISASTER POLITICS)

The remains of a plane that crashed in 2010, killing Poland's former president, Lech Kaczynski and 95 others, is shown to the media at a military aerodrome near the Russian city of Smolensk April 10, 2012. Kaczynski, his wife Maria, and a sizeable chunk of Poland's military and political elite died on April 10, 2010, when their plane crashed in thick fog while trying to land at Smolensk in western Russia. REUTERS/Vasily Fedosenko (RUSSIA - Tags: ANNIVERSARY DISASTER POLITICS)