A member of the staff holds U.S. First Lady Jill Biden's personal bag with a picture of the presidential pets, German Shepherds named Champ and Major, as she prepare to board a plane in Colorado Springs, Colorado, U.S. May 6, 2021. REUTERS/Carlos Barria/Pool

U.S. First Lady Jill Biden steps off a plane upon the arrival at the Colorado Springs Airport, in Colorado Springs, Colorado, U.S., May 6, 2021. REUTERS/Carlos Barria/Pool

An Airbus A320 passenger plane of FlyArystan airline descends against the backdrop of the Tien Shan mountains before landing at an airport in the city of Almaty, Kazakhstan May 4, 2021. REUTERS/Pavel Mikheyev

Planes of German air carrier Lufthansa are photographed at the day of the airline's annual general meeting at the airport in Frankfurt, Germany, May 4, 2021. REUTERS/Kai Pfaffenbach

An airplane of Air Do, a regional airline in cooperation with All Nippon Airways (ANA), is seen next to a Japan Airlines' plane at New Chitose Airport, in Sapporo, Hokkaido, Japan May 4, 2021. REUTERS/Issei Kato

Japan Airlines (JAL) planes sit on the tarmac at New Chitose Airport, in Sapporo, Hokkaido, Japan May 4, 2021. REUTERS/Issei Kato

A Vietnam Airlines plane takes off through a layer of smoke from hazard reduction burns, resulting in a poor air quality alert issued for parts of the city, in Sydney, Australia, May 3, 2021. REUTERS/Loren Elliott

Boeing C-32A plane carrying U.S. Secretary of State Antony Blinken arrives at Stansted Airport, outside London, Britain May 2, 2021 ahead of the upcoming G7 foreign ministers meeting. Ben Stansall/Pool via REUTERS

Ground staff and crew members of the Antonov An-124 Ruslan plane unload Linde tankers after they arrived from abroad to help with coronavirus disease (COVID-19) crisis, at Netaji Subhas Chandra Bose International Airport (NSCBIA) in Kolkata, India, May 2, 2021. REUTERS/Rupak De Chowdhuri

Ground staff unload Linde tankers from the Antonov An-124 Ruslan plane after they arrived from abroad to help with coronavirus disease (COVID-19) crisis, at Netaji Subhas Chandra Bose International Airport (NSCBIA) in Kolkata, India, May 2, 2021. REUTERS/Rupak De Chowdhuri

Crew members of the Antonov An-124 Ruslan plane prepare to unload Linde tankers after they arrived from abroad to help with coronavirus disease (COVID-19) crisis, at Netaji Subhas Chandra Bose International Airport (NSCBIA) in Kolkata, India, May 2, 2021. REUTERS/Rupak De Chowdhuri

Crew members of the Antonov An-124 Ruslan plane unload Linde tankers after they arrived from abroad to help with coronavirus disease (COVID-19) crisis, at Netaji Subhas Chandra Bose International Airport (NSCBIA) in Kolkata, India, May 2, 2021. REUTERS/Rupak De Chowdhuri

Crew members of the Antonov An-124 Ruslan plane prepare to unload Linde tankers after they arrived from abroad to help with coronavirus disease (COVID-19) crisis, at Netaji Subhas Chandra Bose International Airport (NSCBIA) in Kolkata, India, May 2, 2021. REUTERS/Rupak De Chowdhuri

Crew members of the Antonov An-124 Ruslan plane prepare to unload Linde tankers after they arrived from abroad to help with coronavirus disease (COVID-19) crisis, at Netaji Subhas Chandra Bose International Airport (NSCBIA) in Kolkata, India, May 2, 2021. REUTERS/Rupak De Chowdhuri

Medical supplies are transported into a cargo plane to India to help with coronavirus disease (COVID-19) crisis, at Roissy airport, near Paris, France May 1, 2021. Lewis Joly/Pool via REUTERS

Medical supplies are loaded into a cargo plane to India to help with coronavirus disease (COVID-19) crisis, at Roissy airport, near Paris, France May 1, 2021. Lewis Joly/Pool via REUTERS

Medical supplies are loaded into a cargo plane to India to help with coronavirus disease (COVID-19) crisis, at Roissy airport, near Paris, France May 1, 2021. Lewis Joly/Pool via REUTERS

A security officer guards the cargo plane in which medical supplies will be shipped to India to help with coronavirus disease (COVID-19) crisis, at Roissy airport, near Paris, France May 1, 2021. Lewis Joly/Pool via REUTERS

Medical supplies are loaded into a cargo plane to India to help with coronavirus disease (COVID-19) crisis, at Roissy airport, near Paris, France May 1, 2021. Lewis Joly/Pool via REUTERS

Medical supplies are loaded into a cargo plane to India to help with coronavirus disease (COVID-19) crisis, at Roissy airport, near Paris, France May 1, 2021. Lewis Joly/Pool via REUTERS

A U.S. Air Force aircraft carrying coronavirus disease (COVID-19) relief supplies from U.S. prepares to land at the Indira Gandhi International Airport cargo terminal in New Delhi, India April 30, 2021. Prakash Singh/Pool via REUTERS

The Stratolaunch plane, the world's largest, does its 2nd test fight as it comes in for a landing after it performed a 4hr test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins

The Stratolaunch plane, the world's largest, does its 2nd test fight as it comes in for a landing after it performed a 4hr test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins

The Stratolaunch plane, the world's largest, does its 2nd test fight as it comes in for a landing after it performed a 4hr test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins

The Stratolaunch plane, the world's largest, comes in for a landing over Virgin Orbit 747 Cosmic Girl after it performed a 2nd test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins TPX IMAGES OF THE DAY

The Stratolaunch plane, the world's largest, does its 2nd test fight as it comes in for a landing after it performed a 4hr test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins

The Stratolaunch plane, the world's largest, does its 2nd test fight as it comes in for a landing after it performed a 4hr test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins

The Stratolaunch plane, the world's largest, comes in for a landing over Virgin Orbit 747 Cosmic Girl after it performed a 2nd test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins

The Stratolaunch plane, the world's largest, does its 2nd test fight as it comes in for a landing after it performed a 4hr test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins

The Stratolaunch plane, the world's largest, performs a 4hr test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins

The Stratolaunch plane, the world's largest, performs a 4hr test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins

The Stratolaunch plane, the world's largest, performs a 4hr test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins

The Stratolaunch plane, the world's largest, performs a 4hr test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins

The Stratolaunch plane, the world's largest, performs a 4hr test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins

The Stratolaunch plane, the world's largest, performs a 4hr test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins

The Stratolaunch plane, the world's largest, performs a 4hr test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins

The Stratolaunch plane, the world's largest, performs a 4hr test flight in Mojave, California, U.S., April 29, 2021. REUTERS/Gene Blevins

A cargo plane carrying doses of the Chinese Sinovac coronavirus disease (COVID 19) vaccine that were donated by the Chinese government to the CONMEBOL arrives at the Carrasco Airport, in Montevideo, Uruguay April 28, 2021. REUTERS/Mariana Greif

A cargo plane carrying doses of the Chinese Sinovac coronavirus disease (COVID 19) vaccine that were donated by the Chinese government to the CONMEBOL arrives at the Carrasco Airport, in Montevideo, Uruguay April 28, 2021. REUTERS/Mariana Greif

A cargo plane carrying doses of the Chinese Sinovac coronavirus disease (COVID 19) vaccine that were donated by the Chinese government to the CONMEBOL arrives at the Carrasco Airport, in Montevideo, Uruguay April 28, 2021. REUTERS/Mariana Greif

A cargo plane carrying doses of the Chinese Sinovac coronavirus disease (COVID 19) vaccine that were donated by the Chinese government to the CONMEBOL arrives at the Carrasco Airport, in Montevideo, Uruguay April 28, 2021. REUTERS/Mariana Greif

A man inspects the bottom of an Emirates plane carrying a shipment of the Johnson & Johnson vaccine at Toronto Pearson Airport in Mississauga, Ontario, Canada April 28, 2021. REUTERS/Carlos Osorio

An Air Canada plane and an Emirates plane carrying a shipment of the Johnson & Johnson vaccine taxi along a runway at Toronto Pearson Airport in Mississauga, Ontario, Canada April 28, 2021. REUTERS/Carlos Osorio

An Air Canada plane is parked at Toronto Pearson Airport in Mississauga, Ontario, Canada April 28, 2021. REUTERS/Carlos Osorio

Air Canada planes are parked at Toronto Pearson Airport in Mississauga, Ontario, Canada April 28, 2021. REUTERS/Carlos Osorio

An Air Canada plane is towed near a Canada Border Services vehicle at Toronto Pearson Airport in Mississauga, Ontario, Canada April 28, 2021. REUTERS/Carlos Osorio

An Emirates plane carrying doses of the Johnson & Johnson vaccine against the coronavirus disease (COVID-19) lands at Toronto Pearson Airport in Mississauga, Ontario, Canada April 28, 2021. REUTERS/Carlos Osorio

General Wei Fenghe, China's State Councilor and Defence Minister is seen inside the plane as he arrives for an official visit to Sri Lanka, at the Bandaranaike International Airport, in Katunayake, Sri Lanka April 27, 2021. REUTERS/Dinuka Liyanawatte

U.S. First Lady Jill Biden makes her way to board a plane before departing from Albuquerque International Sunport in Albuquerque, New Mexico, U.S. April 23, 2021. Mandel Ngan/Pool via REUTERS

U.S. First Lady Jill Biden pets Chewy, ATF's National Canine Division member (Bureau of Alcohol, Tobacco, Firearms and Explosives), as she makes her way to board a plane before departing from Albuquerque International Sunport in Albuquerque, New Mexico, U.S. April 23, 2021. Mandel Ngan/Pool via REUTERS

U.S. First Lady Jill Biden poses with New Mexico State Police officers as she makes her way to board a plane before departing from Albuquerque International Sunport in Albuquerque, New Mexico, U.S. April 23, 2021. Mandel Ngan/Pool via REUTERS

U.S. First Lady Jill Biden poses with New Mexico State Police officers as she makes her way to board a plane before departing from Albuquerque International Sunport in Albuquerque, New Mexico, U.S. April 23, 2021. Mandel Ngan/Pool via REUTERS

U.S. First Lady Jill Biden poses with an Albuquerque police officer as she makes her way to board a plane before departing from Albuquerque International Sunport in Albuquerque, New Mexico, U.S. April 23, 2021. Mandel Ngan/Pool via REUTERS

U.S. First Lady Jill Biden pets Chewy, ATF's National Canine Division member (Bureau of Alcohol, Tobacco, Firearms and Explosives), as she makes her way to board a plane before departing from Albuquerque International Sunport in Albuquerque, New Mexico, U.S. April 23, 2021. Mandel Ngan/Pool via REUTERS

U.S. First Lady Jill Biden pets Chewy, ATF's National Canine Division member (Bureau of Alcohol, Tobacco, Firearms and Explosives), as she makes her way to board a plane before departing from Albuquerque International Sunport in Albuquerque, New Mexico, U.S. April 23, 2021. Mandel Ngan/Pool via REUTERS

U.S. First Lady Jill Biden poses with New Mexico State Police officers as she makes her way to board a plane before departing from Albuquerque International Sunport in Albuquerque, New Mexico, U.S. April 23, 2021. Mandel Ngan/Pool via REUTERS

U.S. First Lady Jill Biden poses with New Mexico State Police officers as she makes her way to board a plane before departing from Albuquerque International Sunport in Albuquerque, New Mexico, U.S. April 23, 2021. Mandel Ngan/Pool via REUTERS

An aerial view from a plane shows a New Safe Confinement (NSC) structure over the old sarcophagus covering the damaged fourth reactor at the Chernobyl Nuclear Power Plant during a tour to the Chernobyl exclusion zone, Ukraine April 3, 2021. Ukraine International Airlines made a special offer marking the 35th anniversary of the Chernobyl nuclear disaster. Tourists get a bird's eye view of abandoned buildings in the ghost town of Pripyat and the massive domed structure covering a reactor of the Chernobyl Nuclear Power Plant that exploded on April 26, 1986. Picture taken April 3, 2021. REUTERS/Gleb Garanich

Passengers are seen onboard a plane during a tour to the Chernobyl exclusion zone, Ukraine April 3, 2021. Ukraine International Airlines made a special offer marking the 35th anniversary of the Chernobyl nuclear disaster. Tourists get a bird's eye view of abandoned buildings in the ghost town of Pripyat and the massive domed structure covering a reactor of the Chernobyl Nuclear Power Plant that exploded on April 26, 1986. Picture taken April 3, 2021. REUTERS/Gleb Garanich

An aerial view from a plane shows a New Safe Confinement (NSC) structure over the old sarcophagus covering the damaged fourth reactor at the Chernobyl Nuclear Power Plant during a tour to the Chernobyl exclusion zone, Ukraine April 3, 2021. Ukraine International Airlines made a special offer marking the 35th anniversary of the Chernobyl nuclear disaster. Tourists get a bird's eye view of abandoned buildings in the ghost town of Pripyat and the massive domed structure covering a reactor of the Chernobyl Nuclear Power Plant that exploded on April 26, 1986. Picture taken April 3, 2021. REUTERS/Gleb Garanich