E-4B sighting

After pulling up on our driveway we watched the E-4B fly over us. It was so low that we could see in the windows! It's landing gear was still up so I'm not sure why they were flying so low. I wish I had my camera handy but found this photo taken on Offutt AFB, it's the exact view we had. We've seen it many times before but never this close. Pretty cool huh?
The E-4B serves as the National Airborne Operations Center for the president, secretary of defense and the Joint Chiefs of Staff. If needed, the E-4B can provide a command, control and communications center to direct U.S. forces, execute emergency war orders and coordinate actions by civil authorities.
The 55th Wing aircraft was called on to lend a helping hand to the presidential transport aircraft, Air Force One, after it encountered some maintenance issues. The E-4B is a modified Boeing 747 whose mission is to provide support to the national leadership of the United States.