The Biden administration would use the Presidential Drawdown Authority (PDA) to transfer the HAWK equipment which is based on Vietnam-era technology, but has been upgraded several times.The HAWK system is the predecessor to PATRIOT missile defense system made by Raytheon Technologies (RTX.N) which remains off the table for Ukraine, U.S. officials have told Reuters.U.S. President Joe Biden pledged to Ukraine President Volodomyr Zelenskiy that Washington would provide Ukraine with advanced air systems after a devastating missile barrage from Russia earlier this month.One U.S. official said it would likely be about half the size of the recent security assistance packages which have been around $700 million.It was not immediately clear if HAWK interceptor missiles would be included, but U.S. officials have previously cautioned that size and composition of military aid packages can change rapidly."