The Indians have finally tested their indigenous LCA fighter-bomber (a Mirage 2000-5 equivalent) on a ski jump ramp on land. I may not keep as much an eye on aerospace developments as in the 90's, but I still think there was much more echo to this kind of test when the Russians and Chinese did it.
Land-based ski jump ramps are really only for testing and training in preparation for a naval use, but in theory they do shorten the take-off runway length for all aircraft with a tricycle landing gear.
I wondered for a long time whether mobile ramps combined with a land catapult wouldn't have been a superior competitor to rocket-assisted take-off (RATO) and certainly a more practical idea than the zero-length launch efforts (an extreme RATO).
Land catapults were tested; the German Luftwaffe had a prototype (FIST Landflugzeugschleuder Kl 12)* troops-tested in early 1941 already. A piston engine of 320 hp towed and accelerated an aircraft of 14,000 kg to 200 kph on 100 m runway length apparently. He 111 bombers were used for at least some of the tests. I always remember this when I read that the Americans are having trouble with their electromagnetic catapult and are spending money like crazy on it.
Add the normal arresting equipment (well-anchored arresting cables and emergency net) and possibly reinforcing plates for the touchdown area and you could turn a 150-200 m segment of road into an airfield, with all airfield-specific items ready for leaving within ten minutes.
It could have been outright fantastic during the 70's in Central Europe, coupled with F-5Es.
*: I have photos of it and will add them later when I found them..