Page "1972 in aviation" Paragraph 20

* March 31 – In response to the North Vietnamese " Easter Offensive " against South Vietnam which began on March 30, the United States begins a series of deployments code-named " Constant Guard ," in which a large number of U. S. Air Force and U. S. Marine Corps squadrons return to bases in South Vietnam and Thailand and the U. S. Navy aircraft carrier presence at Yankee Station in the Gulf of Tonkin increases from two on March 30 to six by late spring.