An Air Force KC-135 Stratotanker refuels a Canadian Air Force CF-18s over Alaska during Vigilant Shield 2017, a training exercise in the high Arctic. (Photo by Tech. Sgt. Gregory Brook)





A British Airways Airbus A380 aircraft taxis at Heathrow Airport near London, Britain October 11, 2016. (Photo by Stefan Wermuth/Reuters)





A KLM Royal Dutch Airlines Boeing 747-400 with the registration PH-BFY approaching St. Martin airport on February 9, 2014. (Photo by Markus Mainka/Alamy Stock Photo)





A United Airlines aircraft comes in to land at Heathrow airport in west London, Britain October 25, 2016. (Photo by Eddie Keogh/Reuters)





U.S. Democratic presidential nominee Hillary Clinton's campaign plane flies above storm clouds in Seattle, Washington, U.S. October 14, 2016. (Photo by Lucy Nicholson/Reuters)





Cars on the A4 passing a road sign for Heathrow airport as a plane comes into land directly overhead. (Photo by Loop Images Ltd/Alamy Stock Photo)





A United Airlines Boeing 787 taxis as a United Airlines Boeing 767 lands at San Francisco International Airport, San Francisco, California, U.S. on February 7, 2015. (Photo by Louis Nastro/Reuters)





A British Airways aircraft comes in to land at Heathrow airport in west London, Britain October 25, 2016. (Photo by Eddie Keogh/Reuters)





An Iranian military fighter plane flies past an oil tanker during naval manoeuvres in the Gulf and Sea of Oman April 5, 2006. (Photo by Reuters/Fars News)





A Hainan Airlines plane takes off from the Sanya Phoenix International Airport in Sanya, Hainan province, China, May 1, 2015. (Photo by Reuters/Stringer)





An aircraft comes in to land at Heathrow airport in west London, Britain October 25, 2016. (Photo by Eddie Keogh/Reuters)





A U.S. Air Force B-52 bomber receives fuel from a KC-10 tanker aircraft near Iraq October 26, 2016. (Photo by Senior Airman Tyler Woodward/Reuters/U.S. Air Force)





A picture taken on October 25, 2016 shows the construction site of a new cargo complex at Moscow's Sheremetyevo airport as part of preparations for the 2018 FIFA World Cup. (Photo by Vasily Maximov/AFP Photo)





An airplane takes off over the rooftops of nearby houses at Heathrow Airport in Harmondsworth, London, Tuesday, October 25, 2016. Britain's government gave the go-ahead Tuesday to build a new runway at London's Heathrow airport despite concerns about air pollution, noise and the destruction of homes in the capital's densely populated western neighborhoods. (Photo by Frank Augstein/AP Photo)





A U.S. Air Force MQ-1 Predator unmanned aerial vehicle assigned to the California Air National Guard's 163rd Reconnaissance Wing flies near the Southern California Logistics Airport in Victorville, California in this January 7, 2012 USAF handout photo obtained by Reuters February 6, 2013. (Photo by Tech. Sgt. Effrain Lopez/Reuters/U.S. Air Force)





A US Navy F/A-18F Super Hornet launches from the flight deck of aircraft carrier USS Nimitz. (Photo by Stocktrek Images/Getty Images)





Boeing 747-400 of KLM in approach for the “Princess Juliana” airport, Netherlands Antilles Sint Maarten on July 2, 2002. (Photo by LUPOO/Ullstein Bild via Getty Images)





An aeroplane flying above road signs near Heathrow International Airport, London, England. (Photo by Alamy Stock Photo)