President Donald Trump has proposed spending $200B over 10 years on programs to encourage private investors to spend $1 trillion to fix America’s crumbling infrastructure. But when it comes to specifics, it is not clear how he plans to lure that much private investment.

The president gave a hint Monday when he proposed privatizing the nation’s air-traffic control systems, a move that fits into the plan to get states to sell public assets. Trump advisers said they can attract private investors by cutting regulations and permit requirements while encouraging local governments to raise fees, including road tolls and water-usage charges, to generate revenue for investors, the Wall Street Journal reports.

Experts told the Wall Street Journal such measures could help attract investors, but said the real problem is not finding money for projects, but rather a lack of attractive investments. Some experts said they are alarmed by the Trump administration’s decision to cut funding for current programs that support major infrastructure projects while pursuing its own initiative.