Videos are coming in from several states.

airspace priority over DIA and Centennial.

I flew as a navigator on C141 cargo jets, and we were enroute to an airdrop in California one night. About 30 airplanes from all over the East Coast (I flew out of Charleston AFB, SC) were lined up single file at exactly 3000 foot intervals. The controller at Dallas Center said an number of employees had stepped outside to watch the event, it was so unusual.

When military aircraft fly in formation, only the lead aircraft has its transponder (radar identifier) on, hence the tower might have reasonably seen only one aircraft.

My guess it was a formation of C17s.

Threw open their spaceship doors tonight, I reckon they'd have more takers for a trip to another galaxy than they could accommodate.

C17s from Joint Base Lewis McChord around 5:30 pm last night. I would say 25 to 30. That's the most I've personally ever seen leaving together in 35 plus years of living south of the base. They turned east in the general direction of Mount Rainier.