India's left-wing parties, whose support shores up the federal coalition, have opposed the exercises, calling them part of a larger US strategy to set up military bases in the region.
At the Kalaikunda air force base, about 120 km (75 miles) south-west of Kolkata (Calcutta), over 100,000 people raised slogans outside the sprawling defence complex as hundreds of armed police and soldiers stood guard.
"Uncle Sam go away. This is our soil," sang protesters, mostly peasants from nearby villages, as US and Indian fighter jets roared past in mock dogfights.
Activists, who arrived on foot and in crowded trucks, also burned an effigy of US President George Bush.
Protests were also held in Kolkata and other parts of West Bengal, which has been ruled by communists for almost 30 years.
"We are against the exercises because they will jeopardise our national security," Anil Biswas, a senior communist leader, told Reuters.
The exercises are the latest in a series of high-profile military exchanges between India and the United States, whose friendship has warmed considerably in recent years.