Originally posted by Fireking:
For those who are going for this Sat/Sun airforce openhouse at Paya Labar Air Base, you will noticed that the middle lane of Airport Road is closed for the construction of underground Paya Labar Expressway (PLE) at cost of over $1billion stretching from ECP to TPE.
That makes me wonder if is it possible to build one underground / hardened runway to facilitate the launching of our aircrafts when all our available runways/roads are destroyed by enemy MRLS or Artillery during the first strike to demobilise our air force.
I have visited decommissioned air base in Beijing PLAAF Museum where over 100 aircrafts (decomissioned J5 (MiG15), J6 (MiG19), J7 (MiG21), etc) are housed within a huge airbase built inside a mountain - very similar to our Mandai underground ammunition storage facility. Believed that Taiwan also has one such operational airbase built inside the mountains so that fighter planes can be launched during wartime towards the north-east direction (away from mainland China).
In terms of construction technology, I believed that Singapore has already gained much from the construction of the underground MRT, underground ammunition facility and the current PLE. It will not be difficult to build one underground or hardened runway to allow the immediate launch of our fighter aircrafts to carry out counter-strike if our runway / roads are ever destroyed by enemy. Maybe we should consider if it is worth to invest $200 to $500 million building such runway.

Technically speaking. Runways have to be above ground... Hangars and disperal areas can be hardened.
I think it is sufficient to protect aircraft with HAS (Huxley Book) against a first-strike by an adversary. Also when hitting a HAS, you are never sure whether there is an a/c inside.

We have alternate runways like lim chu kang (open source) next to Tengah. We also have other "very straight very long 6 lane highways without a permenant central dividers" in Singapore where in my opinion are alternate runways designate. This is no secret also.
In my opinion, the procedures that the RSAF practice in Lim Chu Kang road can be applied to other roadways.
It will be impossible to repair aircraft and trained personnel once they are bombed as they are both very fragile.
But not easy to bomb runways, Conventional bombs will leave a small crater which will be easily filled by trained units in in airbases (source Huxley). I don't think any potential adversary have specialized runway cratering munitions.
I think we can all restrict our discussion with sources that are unclassified and if it is plain speculation or opinions it should be clearly stated.