After the aircraft's arrival, the supplies were transferred to Myanmar army trucks.
Allowing the US flight is a huge concession by Myanmar's military government, which sees Washington as its enemy.
But Al Jazeera correspondents say the government restrictions on aid agencies and the scale of the crisis means it is not getting through to many badly-hit areas.
In a setback for the aid effort, a Red Cross boat carrying aid has sunk in the hard-hit Irrawaddy delta region after striking a tree branch near the town of Bogolay.
The boat was carrying rice, drinking water and other goods for more than 1,000 people.
The Myanmar military has been sharply criticised for its handling of the disaster, from its failure to provide adequate warnings about the pending storm to responding slowly to offers of help.
'Catastrophe'
David Milliband, the UK foreign minister, said on Sunday that Myanmar's military government had shown "malign neglect" for the people of their country.
With hundreds of thousands at risk of disease, he said "a natural disaster is turning into a humanitarian catastrophe of genuinely epic proportions."
 |
Myanmar has said international aid is welcome,
but not aid workers [EPA] |
Aid agencies have said that with the military government refusing to grant access to relief specialists, many hundreds of thousands of survivors would be at risk of disease.
"The big tragedy would be if people started dieing from preventable diseases," Mlissa Winkler from the International Rescue Committee told Al Jazeera.
"The tragedy is just that – these are preventable diseases."
The crisis in Myanmar was likely to figure high on the agenda of US-China talks taking place.
John Negroponte, the US secretary of state, was expected to urge Chinese officials to put pressure on Myanmar's military to allow more access to foreign aid agencies.
China is Myanmar's biggest trade partner and its closest diplomatic ally.