The USAF operates several dozen Lockheed Hercules MC-130J Commando II aircraft, to transport special forces to and from their operations, refuel associated aircraft in mid-air, and other tasks outside the normal transport function.
Recently a formation of four MC-130J's made several passes through the Mach Loop in Britain, a well-known plane-spotting area where military aircraft of all types practice low-level penetration of enemy airspace. Courtesy of The Aviationist, here it is.
The pilots were clearly enjoying themselves, but I can't help wonder how difficult it was to fly that low. A big transport reacts a lot more slowly than a nimble jet fighter or strike aircraft. If they were a split-second late in responding to the aircraft's movements, it would be all too easy to fly the plane into the ground - not the sort of landing from which one can walk away!