I would suggest the IT Division is now the "good old girls" club. More and more "alternate life styler" women are pushing men out of the middle to upper managerial ranks. They promote each other and sexism has taken a spin the other direction; thus, taking the commitment to diversity too far. The women often dress like men and wear professional pants or jeans (not tight) when not on a customer site. Their hair, in most cases, is shorter then the men.
Business casual is pervasive inside of the Lockheed buildings. It is rare to find someone in a tie, but this, too depends on the Lockheed division. For example, in remote divisions way out in the countryside (Owego, NY), it is not uncommon to see people in tee shirts and "IBM" legacy hats. In more upscale areas, people rarely wear tee shirts and jeans. The Business Development people like to think they are important and wear Sears polyester/wool blend suits, but most of us who do the work laugh at them.
On customer sites, it's always good to look professional and wear suits and ties for men; although, Lockheed does not require this like Booze Allen Hamilton does. Women often wear a nice business suit. Jeans are not promoted on customer sites.