Passengers embrace each other at the entrance to Istanbul's Ataturk airport, early Wednesday, June 29, 2016 following their evacuation after a blast. Suspected Islamic State group extremists have hit the international terminal of Istanbul's Ataturk airport, killing dozens of people and wounding many others, Turkish officials said Tuesday. (Photo by Emrah Gurel/AP Photo)

(L-R), Pilot Gregory H. Johnson, European Space Agency astronaut Roberto Vittori, Mission Specialist Greg Chamitoff, Commander Mark Kelly, Pilot Gregory H. Johnson, Mission Specialist Michael Fincke, and Mission Specialist Andrew Feustel, participate in a Terminal Countdown Demonstration Test (TCDT), at the Kennedy Space Center, on April 1, 2011 in Cape Canaveral, Florida. The TCDT will culminate in a full dress rehearsal for the planned April 19th launch of Space Shuttle Endeavour’s final scheduled flight to the International Space Station before being retired. (Photo by Mark Wilson/Getty Images)

Arnold Schwarzenegger gives a thumbs up as he arrives for the Europe premiere of his new movie 'Terminator: Genisys' in Berlin, Germany, Sunday, June 21, 2015. (AP Photo/Michael Sohn)

Smoke billows from Jinnah International Airport in Karachi, Pakistan, June 9, 2014. (Photo by Athar Hussain/Reuters)

Dust covered seats are pictured inside the lounge of the Jaisalmer Airport in desert state of Rajasthan, India, August 13, 2015. Two-and-a-half years after the completion of a new $17 million terminal building, the airport in Jaisalmer, a small and remote desert city in India's western Rajasthan state, stands empty. (Photo by Anindito Mukherjee/Reuters)

Passengers check their mobile devices as a bin is full of garbage during a protest by the cleaning staff at Barcelona's airport, Spain, December 1, 2016. (Photo by Albert Gea/Reuters)

An Olympic Airways airplane stands on the premises of the former Athens International airport, Hellenikon June 16, 2014. For about six decades Hellenikon was Athens' only airport but it closed down in 2001 to make way for a newer, more modern airport before the city hosted the 2004 Olympic Games. After languishing for years as a wasteland of crumbling terminals, Hellenikon is set for resurrection as a glitzy coastal resort. Lamda Development, controlled by Greece's powerful Latsis family and leading a consortium of Chinese and Abu-Dhabi based companies, has big dreams for the area since signing a 915 million euro deal for a 99-year lease in March 2014. (Photo by Yorgos Karahalis/Reuters)

A sign is posted in front of the new Yoga Room at San Francisco International Airport's terminal two on January 26, 2012 in San Francisco, California. (Photo by Justin Sullivan/Getty Images)