The 747 Supertanker was one of several aerial firefighting airtankers derived from various Boeing 747 models. The aircraft were rated to carry up to 19,600 US gallons (74,000 L) of fire retardant or water. They were the largest aerial firefighting aircraft in the world.

Initially developed by Evergreen International Aviation, the first Supertanker was based on a 747-200 (N470EV, tanker/tail number 947), but never entered service. The second Supertanker (N479EV, tanker/tail number 979) was based on a 747-100 originally manufactured by Boeing in 1971 for Delta Air Lines. It entered service for the first time in 2009, fighting a fire in Cuenca, Spain, and made its first American operation on August 31, 2009 at the Oak Glen Fire in California. It is no longer in service.

The third 747 Supertanker was developed by Global Supertanker Services (which acquired most of Evergreen's assets), who owns and operates the aircraft currently. The Global Supertanker (N744ST, tanker/tail number 944) is a Boeing 747-400 dubbed the Spirit of John Muir. It was certified for firefighting flights by the Federal Aviation Administration in September 2016 and fought fires in Chile and Israel before being contracted by U.S. officials to fight California wildfires in 2017. It also took part in firefighting in Bolivia in August 2019. It was retired in 2021.

The Global Supertanker was equipped with a pressurized liquid drop system, which could disperse fire retardant under high pressure or drop retardant at the speed of falling rain. Using the pressurized system, the aircraft could deliver retardant to the scene of a fire while flying at a height of 400 to 800 feet (120–240 m), at approximately 160 mph (260 km/h; 140 kn), configured as if it were on approach for landing. The Supertanker's tank system could be configured for segmented drops, allowing the contents of the tank to be released at multiple intervals while in flight. According to the company, the aircraft was capable of laying down a swath of fire retardant 3 mi (4.8 km) long and as wide as 150 ft (46 m).

A top speed of nearly 600 mph (970 km/h; 520 kn) allowed it to be almost anywhere in the U.S. in approximately 5 hours and reach most of the world in under 20 hours.

Since May 2016, Global SuperTanker has been based in Colorado at the Colorado Springs Airport, chosen in part for its convenient location for quick deployment to the western US and necessary infrastructure for the large and heavy aircraft.[16] Just a few weeks later, the company was awarded a one-year contract from nearby Douglas County to assist with wildfire containment.

In November 2016, the newer N744ST 747-400 Global Supertanker was deployed to Israel to help fight the wildfires raging in the northern port city of Haifa and elsewhere throughout the country.

In January 2017, the Global Supertanker was deployed to Santiago, Chile, to help the local authorities to combat one of the biggest series of wildfires in the country's history. The wildfires in the south of the country, at the time of the arrival of the 747-400, had burnt more than 494,000 acres (200,000 ha) of forests and hundreds of houses. The operation of the aircraft was the initiative of philanthropist Lucy Avilés and her husband Benjamin Walton, who funded the costs.