Mumbai, March 5 -- India's budget airlines will spearhead the transition to Navi Mumbai Airport, the much-anticipated second airport for the country's financial capital, developed by billionaire Gautam Adani, as it gears up for a planned May opening.

IndiGo, India's largest airline, will relocate part of its operations to the new airport, according to people familiar with the matter who requested anonymity as the information is private.

Tata Group's low-cost carrier Air India Express and smaller rivals SpiceJet and Akasa are also in discussions to eventually relocate all of their operations, the people added.

Air India Ltd.'s full-service carrier will continue to operate from the existing airport for now but will shift more of its dome...