![A C-130 Hercules enters an aircraft hangar during an exercise on Thule Air Base, Greenland, Oct. 17, 2016. The Vigilant Shield 2017 Field Training Exercise is an annual exercise sponsored by The A C-130 Hercules enters an aircraft hangar during an exercise on Thule Air Base, Greenland, Oct. 17, 2016. The Vigilant Shield 2017 Field Training Exercise is an annual exercise sponsored by The](https://c8.alamy.com/comp/P1FJ16/a-c-130-hercules-enters-an-aircraft-hangar-during-an-exercise-on-thule-air-base-greenland-oct-17-2016-the-vigilant-shield-2017-field-training-exercise-is-an-annual-exercise-sponsored-by-the-north-american-aerospace-defense-command-and-led-by-alaskan-norad-region-in-conjunction-with-canadian-norad-region-and-continental-norad-region-who-undertake-field-training-exercises-aimed-at-improving-operational-capability-in-a-bi-national-environment-this-exercise-provides-crucial-training-opportunities-for-numerous-military-personnel-with-a-variety-of-aircraft-and-assets-from-canada-and-the-unit-P1FJ16.jpg)
A C-130 Hercules enters an aircraft hangar during an exercise on Thule Air Base, Greenland, Oct. 17, 2016. The Vigilant Shield 2017 Field Training Exercise is an annual exercise sponsored by The
![Royal Canadian Air Force members arrive for an exercise at Thule Air Base, Greenland, Oct. 17, 2016. The Vigilant Shield 2017 Field Training Exercise is an annual exercise sponsored by The North Royal Canadian Air Force members arrive for an exercise at Thule Air Base, Greenland, Oct. 17, 2016. The Vigilant Shield 2017 Field Training Exercise is an annual exercise sponsored by The North](https://c8.alamy.com/comp/P1FJ12/royal-canadian-air-force-members-arrive-for-an-exercise-at-thule-air-base-greenland-oct-17-2016-the-vigilant-shield-2017-field-training-exercise-is-an-annual-exercise-sponsored-by-the-north-american-aerospace-defense-command-and-led-by-alaskan-norad-region-in-conjunction-with-canadian-norad-region-and-continental-norad-region-who-undertake-field-training-exercises-aimed-at-improving-operational-capability-in-a-bi-national-environment-this-exercise-provides-crucial-training-opportunities-for-numerous-military-personnel-with-a-variety-of-aircraft-and-assets-from-canada-and-the-united-sta-P1FJ12.jpg)
Royal Canadian Air Force members arrive for an exercise at Thule Air Base, Greenland, Oct. 17, 2016. The Vigilant Shield 2017 Field Training Exercise is an annual exercise sponsored by The North
![A C-130 Hercules lands on the flightline of Thule Air Base, Greenland, Oct. 17, 2016. The aircraft carries members of the Royal Canadian Air Force participating in a local exercise. The Vigilant A C-130 Hercules lands on the flightline of Thule Air Base, Greenland, Oct. 17, 2016. The aircraft carries members of the Royal Canadian Air Force participating in a local exercise. The Vigilant](https://c8.alamy.com/comp/P1FJ15/a-c-130-hercules-lands-on-the-flightline-of-thule-air-base-greenland-oct-17-2016-the-aircraft-carries-members-of-the-royal-canadian-air-force-participating-in-a-local-exercise-the-vigilant-shield-2017-field-training-exercise-is-an-annual-exercise-sponsored-by-the-north-american-aerospace-defense-command-and-led-by-alaskan-norad-region-in-conjunction-with-canadian-norad-region-and-continental-norad-region-who-undertake-field-training-exercises-aimed-at-improving-operational-capability-in-a-bi-national-environment-this-exercise-provides-crucial-training-opportunities-for-numerous-milita-P1FJ15.jpg)