There are plenty of stories of large aircraft accidentally, or emergently, landing at airports that don't meet the plane's runway length requirements. The only solution to getting them out that I've read is stripping them to the point that some authority deems them light enough for takeoff on the short runway.
What I haven't read of are the use of any measures to increase the thrust available for the takeoff run. The first idea that came to mind was the use of RATO. Is this possible with civilian aircraft? Is it done? If not, why not?
(My second thought was to temporarily install water injection. But then I figured that by the time a system like that could be tested and approved the plane could have been disassembled for overland shipping.)
The rocket installation was intended for emergency use only when
flying out of a hot and high airport at maximum gross weight. Without
the JATO, the aircraft would have to be payload restricted to account
for the need to reach a safe altitude in the event of an engine loss
after committing to takeoff. By having the JATO provision, Mexicana
could operate its 727-200s at full payload. In the event of a loss of
engine at past V1, the JATO unit would fire and allow the
heavily-laden jet to reach a safe altitude and get aerodynamically
This old video shows a demonstration of that scenario with one of those special 727-200s:
The JATO provision was eventually made obsolete by later developments
in the JT8D engine that featured "APR" automatic power reserve. It
sensed a power decrease from one of the engines failing on takeoff and
automatically boosted the power to the remaining two engines by a
The same reason you give for water injection would apply to RATO. The airframes are not structurally reinforced, nor are there any mounting points or wiring and switches needed for igniting them. It would be a major endeavor to test and certify such a system for the rare occasions when someone might want to have that option.
The difficulty of engineering a RATO is only half the reason, the rest is that reducing weight is really effective.
Typically the empty weight of an airliner is about half the max take off weight. That means that it can accelerate twice as fast, only requiring half the distance to reach the same speed. Also, a lighter plane can take off at lower speeds (although not half, as lift depends on speed squared). Put the two together, and wait for the coldest part of the day when the air is densest and it could manage with about a third of the normal runway.
RATO capability must be designed into the airframe to a certain extent, you need either built-in structural reinforcement and thermal protection or the ability to retro-fit it later. Built-in capability adds weight that airplanes would be lugging around, retro-fit capability costs money to design in, test, certify, maintain and train pilots to use it. All this would add up to significant extra costs for what is best described as a very infrequent edge case. It's cheaper to very occasionally break up an airframe.