nas operational evolution plan air traffic control association global navigation satellite system gnss communications airport landing weather lighting radar ground navaids satcom stations differential integrity tower atct systems atc & the these measures interact ifr example d e m a n an delay c p i t y throughput capacity reduced flight time increases variation in decreases economics as external driver travel trend 1960 2000 revenue passengers enplaned 700 600 500 400 300 200 100 0 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 00 cuban missile crisis hijackings fuel shock patco strike pan am 103 wtc 1993 economic downturn 1974 75 1980 1982 1991 actual growth sse g r s l ed o gulf
