The attack, in which four fighters were also killed, took place on Friday in the Uruzgan province, where the Taliban frequently attack US and Afghan government forces and where a US soldier was killed in a Taliban ambush on Tuesday.
"The attack killed one Afghan woman, one Afghan man and a child. Two children were also wounded," the US military said in a statement on Saturday.
"All possible efforts are taken to prevent non-combatant injuries and deaths," it said.
The US military gave no details on the aircraft involved; most planes and helicopters in the 18,300-strong US-led international force in Afghanistan belong to the United States.
US-led forces toppled the Taliban government in late 2001 after it refused to hand over al-Qaida leader Usama bin Ladin following the 11 September attacks on the United States.
Taliban fighters have fought on, however, and attacks have picked up in recent weeks after a lull over the winter.
Poppy crop destroyed
Last year, Afghanistan supplied
87% of the world's illicit opium
In another development, Afghan authorities on Saturday sent police to northern Afghanistan to destroy opium poppy crops, the Interior Ministry said, expanding a crackdown on the world's largest illegal drug industry.
An undisclosed number of federal police were sent to Balkh, which includes the main northern city of Mazar-e-Sharif, because of a significant increase in poppy cultivation in the province, a ministry statement said in Kabul.
Donors, including the United States and Britain, are funding an effort to eradicate poppy fields, smash drug labs, arrest traffickers and help farmers switch to alternative crops.
Violent clashes between farmers and teams sent to destroy their crops have marred recent eradication efforts in the south and west of the country.
Last year, Afghanistan supplied an estimated 87% of the world's illicit opium, the raw material for heroin, sparking warnings that it is turning into a "narco-state".