Real possible explanation (conjecture): During the events of the past few days, has heightened security or emergency alerts caused an abnormal number of military planes to be in the air at the same time? Afterwards, these aircraft have to be serviced and the pilots "run out of hours" and have to have ground time to rest. Also, if an expected event is in the near future, they would be prepping aircraft, getting in maintenance, loading equipment and weapons. Also, the pilots would be briefing and resting. We know the NG already have ground troops on alert and they will stay on alert for the next 30 days, through the inauguration and beyond. It is not out of line to consider that the air force and other agencies would be doing the same thing, especially given the events of the past days and the heightened tension. This does not necessarily mean that they are going to perform military action. But they may have to prep for it even though it won't be needed. A lot of military action is doing patrols and guarding, not shooting and dropping bombs. Edit: It is also possible due to heightened security that they were ordered to run silent. They can turn their ADSB transponders off.