The Biden administration's latest infusion of more than $2.7 billion in military aid for Ukraine and the promise of billions more will give Kyiv a massive boost in air defenses, but much of the aid is in long-range contracts for weapons that won't be seen on the battlefield for some time. Included in a $2.4 billion long-term assistance package announced Thursday — just before meetings between Ukrainian President Volodymyr Zelenskyy and President Joe Biden and Vice President Kamala Harris — is another Patriot missile battery and additional munitions for the system. Patriots are critical air defense systems that the U.S. military uses around the world to protect American forces and allies. It is a high-demand air defense capability, and the U.S. has a limited number of them and the missiles they fire. The system is being provided through the Ukraine Security Assistance Initiative, which funds longer-term contracts.