Witnesses said AC-130s - cargo aircraft equipped with cannon and machine guns - were in action for at least half an hour late on Wednesday while tanks shelled the town on the ground.
The bombardment was said to be the heaviest on the town for several weeks.
The US military is poised for an offensive on Falluja, some 50km west of Baghdad, to flush out armed men resisting its forces.
Speaking to Aljazeera from Falluja, Iraqi journalist Abu Bakr al-Dulaimi said the city's citizens feel that US communiques about an imminent large-scale attack against their city and Ramadi is an attempt to destroy their morale.
US military officials have been
promising an attack on Falluja
"However, the possible attack on Falluja does not affect their high spirits," he added.
"Falluja citizens have showed indifference towards Bush's re-election as they believe the US policies are clear and consistent when dealing with Islam, Muslims and the Iraq case," al-Dulaimi pointed out.
Earlier in the day, attacks by US warplanes sent up plumes of black smoke from the eastern edge of Falluja.
A woman was seriously wounded and a teenage girl lost her right leg in the strikes, hospital official Isam Muhammad said.
The US-backed Iraqi interim government has threatened to wrest control of Falluja from the Iraqi fighters before elections scheduled for January.
Residents of the city say the daily bombardments cause heavy civilian casualties and increase resentment against the United States.