RE: Retract Air Pump
I think this is a case where you can go cheap and get away with it.
I use a 9$ 12 volt tiny compressor from Canadian Tire, I run it off my 12 volt field box battery. ( now I use a 3 cell LiPo in my field box, it'slighter than the old wet cell, and cheaper!
It pumps up my systems quick and has last for 10 years now!! When it dies, I just get another.
Just cut the air hose off at the end, then use Goop glue and slide in your rc air line to the length you want and attach the correct end.
Presto