The government plans to invest $30 billion in the next 10 years with more existing airports being opened up for modernisation, a top official said on Tuesday. "In 10th and 11th five-year plans, the government invested $10 billion. The airports developed under the public-private-partnership model are presently handling 60 per cent of the passenger traffic in the country. The government has planned to invest $30 billion in the next 10 years," civil aviation secretary S N A Zaidi on Tuesday.