Investors are piling into defense stocks: ​Aerospace & Defense ETF inflows hit $8.2 billion in the first three quarters of 2025. ​That’s a +573% surge compared to 2024. ​ Monthly inflows peaked at $1.6 billion in June, before easing to $634 million in September. ​ The boom has spurred 17 new Aerospace & Defense ETFs launched in 2025—up from just 2 last year. Investor appetite for defense exposure is stronger than ever.