AFTER six years of lobbying by carriers and travellers on both sides of the Causeway, budget airlines began flying the Singapore-Kuala Lumpur route on Friday, ending 30 years of fare-fixing by the national carriers and opening the way for wider liberalisation of the region's air corridors.

First to enter the sector was Malaysia's AirAsia which left KL at 10am and arrived at Changi Airport Terminal 1 about 40 minutes later, where official speeches and a ceremony had been laid on to welcome the passengers.

Minutes after that, Tiger Airways took off from Changi - with three out of four seats taken up mainly by holiday makers and a handful of business travellers - and landed at KLIA's budget terminal just before noon.

AirAsia will fly the sector twice a day while Tiger Airways and Jetstar Asia - which operates an afternoon flight - will fly once a day between the two cities.

Travellers who used to pay $440 for a round-trip ticket on Singapore Airlines and Malaysia Airlines which dominated the market before this, welcomed the lower fares that came with liberalisation.

To lure the flying public, low-cost carriers have offered big discounts - including some seats priced at zero dollars before taxes - to inaugurate their new services.

Not to be outdone, incumbents SIA and MAS recently ended more than 30 years of fixing fares and sharing revenues on the Singapore-KL route - a strategic move to allow them to be more nimble, so they can compete effectively with the new kids on the block.

They now have a code-share agreement instead, which means that a passenger holding an SIA ticket can also fly with MAS and vice-versa.

By December, the Singapore-KL route will be fully liberalised under a pact by the 10-member Asean grouping to remove all restrictions on passenger flights between capital cities.

Until then, the governments are not expected to give the green light for more budget flights.

Civil Aviation Authority of Singapore (CAAS) director for airport management, Mr Foo Sek Min, who was at Terminal 1 to welcome the first AirAsia passengers said the opening of the market will be good for travellers and both cities.

Last year, 2.5 million passengers flew between Singapore and KL - a number that looks set to grow with the entry of low-cost carriers.