If the SIN govt was so protective of SIA, why would they invest in Jetstar Asia and Tiger Airways and allow Valuair to set up? 3 airlines based in Singapore in direct competition with SIA.

I do agree that the government is protective of CHANGI Airport, not SIA. They are going through all lengths to protect Changi's hub status - As far as they're concerned, Jetstar Asia and Valuair stimulate more traffic out of Singapore regardless of whether they are a threat to SIA.