Hindustan Aeronautics Ltd (HAL), public sector defence aerospace major, plans to invest Rs 17,500 crore spread over 5-6 years for modernisation of its manufacturing facilities, develop and upgrade aircraft. The government has recently sanctioned funds to the tune of Rs 1,000 crore for doubling the production capacity of Tejas fighter planes from 8 to 16. Funds would be raised through loans and equity.