When you think of the German Autobahn, you probably fantasize about burning rubber without worrying about getting a speeding ticket. What might not come to mind is that NATO plans for World War III intended for the Autobahns to do more than just move motor vehicles.
Some stretches of the Autobahn were meant to be used as emergency airstrips. This was actually some extremely prudent planning on NATO's part. The problem with air bases is that they're hard to hide, even in the days before Google Earth made hiding nearly impossible.
The operating assumption was that the Warsaw Pact was going to try to shut down those airbases by cratering runways, blasting facilities, and, if they were in a particularly nasty mood, they'd follow up those attacks by "sliming" the bases with persistent chemical agents. Now, this had the potential to be a very serious problem for NATO, since the Warsaw Pact's war plans involved hordes of tanks, armored personnel carriers, infantry fighting vehicles, infantry, and artillery directed at NATO.
In the event of World War III, the A-10 was intended to thin out the hordes of Russian troops and vehicles heading to the front.
To stop those hordes, NATO relied on very responsive close-air support. There were two approaches to handling the only real option NATO had: One was to develop jets that could operate from very short fields, like the Harrier, used by both the Royal Air Force and the United States Marine Corps. The other approach was to find makeshift runways, outside of obvious airbases.
While tankers like the KC-135 could allow A-10s to operate further from the battle, there would be an unacceptable increase in response time.
The Autobahn was a natural selection for such a task, since it's wide enough and long enough to operate planes like the A-10. Plus, it would allow Harriers to use rolling takeoffs, thus enabling them to carry more bombs.
Of course, all of these plans were put in place for a war that never materialized — but the treat once felt very real and very imminent. So, on occasion, NATO would practice operations from the Autobahn, so that should a real war break out, they were ready to keep planes like the A-10 Thunderbolt in the fight. The A-10s could then remain more responsive to troops fighting on the ground, rather than having to operate from bases further back from the lines.
Today, the A-10 still carries out exercises intended to send Moscow a very strong message.
You can see how the A-10s managed to get their Autobahn operations practice in the video below. Thankfully, such capability hasn't yet been needed — but A-10s still carry out exercises intended to send Moscow a message today.