Update 6/25 10 p.m.
A spokesperson from the 317th Airlift Group told us the military planes spotted Monday night were part of a training exercise between the U.S. Air Force and Army.
It was part of a multi-day training operation called Joint Operations Access Exercise, where the group works with various Air Force units to support the Army as it trains for wartime situations.
We're told this was the largest training formation of C-130s to take flight since Sept. 11, 2011.
We took several calls from people in Roanoke City, Southside, Franklin County and Craig County Monday about twenty or more planes flying in a "straight line" formation.
We confirmed with Roanoke Regional Airport that the planes are part of military training.
We also talked with stations in Virginia Beach, and they have had similar calls.