TERROR PLOT(01 of14)
Open Image ModalTravelers wait in a security line at the Philadelphia International Airport in Philadelphia, Thursday, Aug. 10, 2006. Airports tightened security and delayed flights in the wake of a terror plot discovery in Britain. (AP Photo/Matt Rourke) (credit:MATT ROURKE/AP)
US Airways(02 of14)
Open Image ModalIn this Friday, Oct. 29, 2010 photo, an US Airways jet airplane approaches Philadelphia International Airport in Philadelphia. (AP Photo/Matt Rourke) (credit:Matt Rourke/AP)
Airports Suspicious Packages(03 of14)
Open Image ModalInvestigators board a United Parcel Service jet isolated on a runway at Philadelphia International Airport in Philadelphia, Friday, Oct. 29, 2010. Law enforcement officials are investigating reports of suspicious packages on cargo planes in Philadelphia and Newark, N.J. (AP Photo/Matt Rourke) (credit:Matt Rourke/AP)
Southwest Airlines Boeing 737-300 N645SW(04 of14)
Open Image Modal[UNVERIFIED CONTENT] Plane is inbound about 10 miles from Philadelphia International Airport. (credit:Brian Kushner via Getty Images)
AMR US Airways Merger(05 of14)
Open Image ModalUS Airways jets prepare for flight at their gates at the Philadelphia International Airport, Thursday, Feb. 14, 2013, in Philadelphia. The merger of US Airways and American Airlines has given birth to a mega airline with more passengers than any other in the world. (AP Photo/Matt Rourke) (credit:ASSOCIATED PRESS)
AMR US Airways Merger(06 of14)
Open Image ModalAmerican Airlines and US Airways jets park at gate at the Philadelphia International Airport, Thursday, Feb. 14, 2013, in Philadelphia. The merger of US Airways and American Airlines has given birth to a mega airline with more passengers than any other in the world. (AP Photo/Matt Rourke) (credit:ASSOCIATED PRESS)
Gatwick Airport Is Closed Due To Security Alert(07 of14)
Open Image ModalGATWICK, UK- FEBRUARY 13: (FILE PHOTO) A police officer stands guard at Gatwick airport's north terminal after a security scare February 13, 2003 in Gatwick, United Kingdom. Part of Gatwick Airport was closed late September 12, 2003 after the discovery of a 'suspect vehicle' near the South Terminal. Bomb disposal experts were called to the area to investigate. (Photo by Ian Waldie/Getty Images) (credit:Ian Waldie via Getty Images)
Security Visible At Nations Airports Prior To 4th Of July Celebrations(08 of14)
Open Image ModalSAN FRANCISCO - JULY 3 : San Francisco police officer Carlos Cordova and his dog Fax patrol the ticketing area of the International Terminal at the San Francisco International Airport on July 3, 2007 in San Francisco, California. The Transit Security Administration (TSA) has deployed 'VIPER' teams of armed officers and dogs to help patrol airports and mass transit hubs nationwide after the UK bombing scare and to increase security over the Independence Day holiday. (Photo by David Paul Morris/Getty Images) (credit:David Paul Morris via Getty Images)
Security Visible At Nations Airports Prior To 4th Of July Celebrations(09 of14)
Open Image ModalSAN FRANCISCO - JULY 3 : San Francisco police officer Carlos Cordova and his dog Fax patrol the ticketing area of the International Terminal at the San Francisco International Airport on July 3, 2007 in San Francisco, California. The Transit Security Administration (TSA) has deployed 'VIPER' teams of armed officers and dogs to help patrol airports and mass transit hubs nationwide after the UK bombing scare and to increase security over the Independence Day holiday. (Photo by David Paul Morris/Getty Images) (credit:David Paul Morris via Getty Images)
Manchester Airport Shuts Down After Suspected Bomb Attempt(10 of14)
Open Image ModalMANCHESTER, ENGLAND - SEPTEMBER 23: Police watch the area around Terminal 1 of Manchester Airport where passengers were evacuated after an incident between Terminals 1 and 2, on September 23, 2005 in Manchester, England. A man has been arrested under the Terrorism act following the incident. (Photo by Alex Livesey/Getty Images) (credit:Alex Livesey via Getty Images)
Manchester Airport Shuts Down After Suspected Bomb Attempt(11 of14)
Open Image ModalMANCHESTER, ENGLAND - SEPTEMBER 23: Police watch the area around Terminal 1 of Manchester Airport where passengers were evacuated after an incident between Terminals 1 and 2, on September 23, 2005 in Manchester, England. A man has been arrested under the Terrorism act following the incident. (Photo by Alex Livesey/Getty Images) (credit:Alex Livesey via Getty Images)
Philippines Bomb Scare(12 of14)
Open Image ModalPhilippine National Police bomb squad unit checks an abandoned luggage outside the departure area of the Ninoy Aquino International Airport Terminal 3 Monday, Sept. 1, 2014 at suburban Pasay city, south of Manila, Philippines. Airport security has been increased Monday after four men were taken into custody by the National Bureau of Investigation agents at the parking lot of the NAIA Terminal 3 hours earlier. (AP Photo/Bullit Marquez) (credit:ASSOCIATED PRESS)
Philippines Bomb Scare(13 of14)
Open Image ModalPhilippine National Police bomb squad unit checks the contents of an abandoned luggage outside the departure area of the Ninoy Aquino International Airport Terminal 3 Monday, Sept. 1, 2014 at suburban Pasay city, south of Manila, Philippines. Airport security has been increased Monday after four men were taken into custody by the National Bureau of Investigation agents at the parking lot of the NAIA Terminal 3 hours earlier. (AP Photo/Bullit Marquez) (credit:ASSOCIATED PRESS)
Philippines Bomb Scare(14 of14)
Open Image ModalPhilippine National Police bomb squad unit checks the surrounding outside the departure area of the Ninoy Aquino International Airport Terminal 3 Monday, Sept. 1, 2014 at suburban Pasay city, south of Manila, Philippines. Airport security has been increased Monday after four men were taken into custody by the National Bureau of Investigation agents at the parking lot of the NAIA Terminal 3 hours earlier. (AP Photo/Bullit Marquez) (credit:ASSOCIATED PRESS)