E-6B Mercury planes, also know as "Doomsday planes," are designed to be communications relays during nuclear war, according to Popular Mechanics. The planes have the ability to be a communications backup between the president and the country's missile apparatuses.
Trump, around 11:50pm CT, announced that he and First Lady Melania Trump had tested positive for the coronavirus and would begin quarantining.
However, shortly before Trump's tweet, Twitter user @TimInHonolulu noted that two E-6B Mercury planes were flying on both coasts. One plane was spotted along the coast of Maryland and Delaware. The other plane was spotted near Oregon, according to @TimInHonolulu's tweets.
The spotting of the planes led to a lot of speculation about the timing of the flights—specifically if they were there as a safety precaution in the wake of Trump's coronavirus announcement.
But it appears that the flights weren't anything out of the ordinary.
A U.S. Strategic Command spokesperson told the Daily Dot on Friday morning that they could confirm that flights were "pre-planned" and that "any timing to the president's announcement is purely coincidental."
Other reporters and Twitter users noted that E-6B planes are in the air routinely, and stressed that it was a jump to speculate about the timing.