For this case I made the variable _repeat in my script!
Just rename _repeat to a global Variable like glREPEAT
This would be line 27:
_repeat = true
change in
glREPEAT = true
and change in line 57
?_repeat && alive _this : goto "repeat"
into
?glREPEAT && alive _this : goto "repeat"
There is one thing, if you set glREPEAT to false, then the effect takes not place immediately, you had to end the effect by flying fast or high. But you may additionally alter line 55
Original:
?(getpos _this select 2) < 30 && speed _this < 120 && isEngineOn _this: goto "loop"
And new:
?(getpos _this select 2) < 30 && speed _this < 120 && isEngineOn _this && glREPEAT: goto "loop"
This should work. Now you may disable the script by just setting glREPEAT to false. If you want it to appear again, execute the script.