"... far from any signs of civilisation"
What kind of stupid remark is that...
KLIA is 28 minutes on the ERL from the centre of KL
Changi is 30 minutes from Singapore on the MRT
Paris-Roissy (Charles de Gaulle) is one hour from Paris on the RER
Stansted is 45 minutes on BR from London
Gatwick is something similar from London
Heathrow is 15 minutes from Paddington + taxi or tube to wherever.
And if you think Subang is closer than that to KL you must be on something. There is no timetabled passenger service from Subang to KL, your best bet is a couponed taxi.
The original alignment for the PUTRA LRT to Subang has now been taken over by a developer for condominiums, so nothing will be happening there.
And isn't the MAS hangar mentioned by SuperRanger on the "otherside" of the Jalan Terbang..... (will willingly stand corrected on that)
KLIA is great I regularly fly back from South Africa and Europe, and can guarantee to be at home in downtown KL one hour fifteen minutes after touchdown.