RATO used to get civilian aircraft out of airports with inadequate runway length?
The DH Comet was equipped with RATO.

The Fairchild SA226 had a RATO bottle in the tail to improve single engine performance.  As I recall, removing the spades on the main landing gear eliminated enough drag to render the RATO unnecessary.

Boeing built twelve "727-200/JATO" variants for use by Mexicana Airlines.



  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
  cleaned up.


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
  significant margin.