Father and son's privately held travel group, InterGlobe Enterprises, recently got regulatory approval to list flagship IndiGo, the country's biggest and most profitable domestic airline. The IPO is expected to value the 9-year-old budget carrier, known for its punctuality, at $3.8 billion. In what was the biggest ever order for single-aisle aircraft received by Airbus, IndiGo purchased 250 planes in August for $27 billion. The airline has successfully faced off new rivals such as Malaysian tycoon Tony Fernandes' Air Asia India, and Vistara, a JV between Tata Group and Singapore Airlines. The Bhatias' other interests include a string of hotels in a joint venture with France's Accor.