“The C-17 fleet has been the workhorse of the UAE's Covid aid distribution efforts [and] used in direct support of joint UAE-US security missions,” the embassy said on Twitter in reference to the deal.
The massive plane was developed in the 1980s and had its maiden flight in the 1990s. It is renowned for carrying people and cargo around the world.
Powered by four engines, it is 53 metres long and has a wingspan of 51 metres.
Known as the “Globemaster”, the C-17 can also take-off from and land on short runways and unconventional airfields owing to its design, a US fact sheet about the plane has said.
“The UAE has been, and continues to be, a vital US partner for political stability and economic progress in the Middle East,” a release from the Pentagon's Defence Security Co-operation Agency said about the deal.
The Emirates has used the cargo plane to great effect as part of global efforts to tackle the Covid-19 pandemic.
In 2020, as the first waves of infection caused havoc around the world, the UAE sent one of its C-17s to Ghana, carrying parts of a field hospital to support a UN mission protecting aid workers.
A video posted by David Beasley, the director of the UN’s World Food Programme, showed crucial supplies being offloaded from the C-17 at the time.
“I picked up the phone and called His Highness [President Sheikh Mohamed], saying, 'Brother, we need help. People are suffering,'” Mr Beasley said.
“He did not blink an eye and immediately said, 'We will help.' People of the UAE and the leadership, Mohamed bin Zayed, my dear brother, thank you for the kindness of your heart to help people save lives.”
A crew of three typically operates the plane, which can carry vehicles can cargo and has a range of about 4,445 kilometres.
Apart from the US and the UAE, the C-17 is in service in countries such as the UK, Australia, Canada and Kuwait.
The Defence Security Co-operation Agency notified the US Congress of the potential sale. However, an announcement regarding the signing of a formal contract was not made.