Evergreen International Aviation became his flagship company. At its peak, it was one of the largest air freight companies in the world. It also carried passengers on charter flights worldwide. Over the years, it flew many important missions. Evergreen transported the Shah of Iran into exile when his government collapsed in 1979. The company helped the World Health Organization deliver aid to Africa and delivered supplies used to extinguish the oil well fires in Kuwait. It also supported United States military operations around the world including Desert Shield, Desert Storm, Kosovo, Afghanistan, and Iraq in 2003. Evergreen supported United Nations peacekeeping missions in 30 countries and conducted drug eradication operations in Mexico and South America. The National Aeronautics and Space Administration's Space Shuttle Carrier was maintained at Evergreen's Arizona depot.