Can anyone tell me how long it might take to get through security at National Airport on a Friday late afternoon? A flight I am looking at leaves at 5:45, but I know that I cannot get to the airport before 4:45. I will have done web check in and will have carry on only. Is that enough time to get through. On my last visit to DC I seem to remember security being quite efficient--that was two years ago. If I cannot make that flight, then I am better off staying the night and flying out in the morning as I cannot get all the way home any later than that. I would rather get home on the Friday as I will have been away for almost two weeks.