Silk Air flies from Singapore to Phuket (it's a subsidiary of Singapore Air). It's a regional airline but not a discount airline. I'm not sure if Tiger Air flies that route, but it is a discount airline based in Singapore. Air Asia is another discount airline. It does not fly between Singapore and Phuket, but does fly between Phuket and Bangkok. It's base is in Kuala Lumpur.

Tiger airlines does (or used to) we found them excellent. (they are VERY strict about excess baggage though)

Is there a preference between Tiger airlines and AirAsia? I am more concerned about reliability and safety than comfort.

Thanks!

They have both gotten good reviews here. They both have the disadvantages of budget airlines: low baggage allowance and charges for excess, if you miss a flight you have to buy a new ticket, etc. But if the restrictions are ok with you, both are safe. Air Asia got a bad rap for a while because it would change flight times (dramatically, like by 12 hours) or cancel flights without notice. I haven't heard any recent complaints about that.

Tiger airlines are the higher end of the budget airlines scale and we found them excellent, i would definately recommend.

From Singapore to Phuket there are 3 airlines - Air Asia, Tiger and Jet Star (on certain days).

From Phuket to Bangkok there are Air Asia, Nokair and One-Two-Go. The former two land at the old airport Don Mueang.

You will have to check your dates on each airline to get a fare comparision and take into consideration baggage allowance and extra cost.