I'm going to the Mid-Atlantic Air Museum's World War II Weekend tomorrow and I think I'm going to wear my 1940's gabardine trousers. I'm using the picture above as a resource to what direction I'm thinking of going in. I found this awesome pair of pants at an estate sale about a year ago. The woman who owned them was a WAC during WWII. She had saved all of her military uniforms and some of her civilian clothes from that time. I was able to purchase her 1940's suit and pants. Last year they were a wee bit snug on me but now they fit perfect!
Finding a vintage pair of 1940's gabardine trousers can be a difficult task but different sites such as Vivien of Holloway and ReVamp Vintage are making reproduction pants. If you keep your eyes open, you can run across them from time to time on Ebay.