Fleeing the hot, humid air of the plains around Rawalpindi, Henry A. Kissinger, President Nixon's national security adviser, spent the day at Nathiagali in the cool hills of northern Pakistan. Although he was described as “feeling slightly indisposed,” Mr. Kissinger had lunch with Gen. Abdul Hamid Khan, chief of staff of the Pakistani Army. Mr. Kissinger, on a global tour, was said to have discussed with the general the curtailment of United States military aid to Pakistan after civil war erupted in East Pakistan in March.