** Shares of defense companies Northrop Grumman NOC.N, RTX RTX.N, and Lockheed Martin LMT.N fall 11.1%, 8.1%, and 2.8%, respectively, after Q1 results

** NOC on track for its worst day since 2008

** NOC and RTX leading declines on the benchmark S&P 500 index .SPX

** NOC posts 49% drop in Q1 profit and misses sales expectations, after booking losses on its B-21 stealth bomber program due to higher manufacturing costs

** RTX reports better-than-expected Q1 profit and reaffirms its annual outlook; however, shares fall after co says tariffs could hurt profit by about $850 million over the year

** LMT shares decline despite reporting higher Q1 profit and reaffirming its forecasts for the year

** Including session's move, NOC up 0.7%, RTX up 0.6% and LMT down 7.9% YTD vs a 0.8% YTD rise in S&P 500 Aerospace and Defense sector index .SPLRCAERO

(Reporting by Sukriti Gupta)

((Sukriti.Gupta@thomsonreuters.com;))