Expert Airmen Primarily Right Stuff For Sound Barrier

• an earphone that is inserted into the ear canal

• a plug of cotton, wax, or rubber that is fitted into the ear canal for protection against the entry of water or loud noise

• a war measure that isolates some area of importance to the enemy

• prevents access or progress

• hinder or prevent the progress or accomplishment of

• render unsuitable for passage

• obstruct access to

• impose a blockade on

• an agency focused on ensuring that the United States military attains information superiority; operates worldwide ground sites and an array of airborne reconnaissance and surveillance platforms