The Air Force's E-4B "Nightwatch," the airborne command post built to run a nuclear war, took off from Offutt Air Force Base in Nebraska on Thursday and flew east across the Midwest on a mission nobody has explained.

Flight-tracking data reviewed by the Daily Mail shows the jet crossing Illinois and Indiana into Ohio, where it was tracked at about 2:41 p.m. Eastern at 31,000 feet and a ground speed of 573 knots, roughly 660 mph. It then turned south over northern Virginia, west of Washington. The tracking images listed no destination, and the route alone does not show where it was headed or why. The purpose of the flight and the identities of anyone aboard have not been publicly confirmed, the Mail reported.

The E-4B is the National Airborne Operations Center: a modified Boeing 747-200 meant to let the president and senior military leaders direct U.S. forces, nuclear forces included, if ground command centers are destroyed. The Air Force flies four, all based at Offutt, and the Mail noted that one is kept ready around the clock when the president is in the country.

That keeps the innocent explanation in play. The same jets fly routine training and readiness missions, and a flight out of their home base is not in itself a sign of an emergency.

The airframes are a 1970s design, and the Air Force is paying for their replacement. In April 2024 it gave Sierra Nevada Corp. a contract worth about $13.08 billion to build the Survivable Airborne Operations Center, with work expected to run until July 10, 2036, according to The Aviationist. The aircraft type has not been announced.

The sighting comes as the Pentagon is working on continuity plans of its own. As we reported, it is planning for its major bases to survive 90 days without the power grid.