WASHINGTON, March 4 (Reuters) - U.S. President Donald

Trump has frozen military aid to Ukraine, just days after

publicly confronting Ukrainian President Volodymyr Zelenskiy at

the White House and accusing him of being insufficiently

grateful for Washington's backing.

The halt to U.S. military aid does not only have significant

implications for the three-year-old war between Ukraine and

Russian invasion forces. It will also impact the U.S. defense

industry. Here's how:

HOW MUCH HAS THE U.S. SPENT ON MILITARY AID FOR UKRAINE?

The United States has pledged and spent at least $65 billion

on military aid for Ukraine since Russia's full-blown February

2022 invasion. Primarily, that assistance has been allocated

through two tools: the Presidential Drawdown Authority (PDA) and

the Ukraine Security Assistance Initiative (USAI).

WHAT IS THE PRESIDENTIAL DRAWDOWN AUTHORITY?

More than $31 billion worth of weapons and equipment has

been pledged to Ukraine under the Presidential Drawdown

Authority (PDA), which allows the president to approve rapid

transfers to foreign countries from U.S. military stockpiles,

without having to seek congressional approval.

More than $20 billion worth of weapons and equipment has already

been shipped this way, according to a Reuters analysis.

Ukraine is still awaiting a large shipment of armored

vehicles that are not set to be delivered until mid-2025, said a

Ukrainian official, speaking on condition of anonymity. They are

currently being refurbished at depots in Europe.

WHAT IS THE UKRAINE SECURITY ASSISTANCE INITIATIVE?

The U.S. has bought nearly $33.2 billion worth of new arms

and military equipment for Kyiv directly from U.S. and allied

defense contractors. That money was allocated by Congress.

The USAI is a longer-term approach to arming Ukraine. It will

take years for all these weapons to be manufactured and shipped

to the battlefield. This category of weapon provides Ukraine a

sustained pipeline of modern weaponry and simultaneously

sustained revenue for manufacturers.

The amount of aid that still needs to be delivered from the

American contracts is "significantly less than 15 percent", a

Ukrainian official said. Some of the weapons still to be

delivered include advanced rocket launchers and missiles.

HOW DOES THIS AFFECT U.S. COMPANIES?

The halt to USAI not only impacts current orders, but also

future production plans and investment decisions for U.S.

companies such as L3Harris Technologies ( LHX ), Lockheed Martin

Corp ( LMT ), RTX Corp ( RTX ) and General Dynamics ( GD ).

It's unlikely that the U.S. government would cancel the

orders for Ukraine that have not yet been delivered. It could

decide to keep those weapons for itself.

Washington needs to replenish its own stocks and - instead

of placing new orders - could instead keep the weapons that were

bound for Ukraine, essentially reducing the future amount of new

contracts on offer to U.S. companies.

WHAT WEAPONS HAVE BEEN DELIVERED TO UKRAINE?

Among the weapons and equipment provided during the war are

U.S.-made F-16 fighter jets, long-range ATACM missiles, High

Mobility Artillery Rocket Systems (HIMARS), the Guided Multiple

Launch Rocket System (GMLRS), short-range air defense

interceptors, replacement vehicles, air-to-ground munitions, and

artillery.