More flights and choices for travellers will come only when the 10-member countries--Brunei, Cambodia, Indonesia, Laos, Malaysia, Burma, the Philippines, Singapore, Thailand and Viet Nam--ratify the agreement.
Some, like Indonesia, are still undecided.
Tri S Sunoko, the Transport Ministry's director of air transportation, told The Straits Times in a telephone interview that no decision had been made on when an existing ban on foreign budget carriers would be lifted.
He said: "We support the principles of liberalisation but this is something we will embark on step by step. I cannot say at this time when we will open up more routes to foreign airlines.
"We first have to ensure that our national carriers are in a position to compete effectively with the other regional airlines."
The need to protect its fledgling air transport industry was cited by the Indonesian authorities in 2005 when they banned foreign low-cost airlines from flying to four key cities--Jakarta, Medan, Surabaya and Denpasar (Bali).
On whether the current global financial turmoil, which has hit airlines everywhere, would delay the process of liberalisation, Sunoko reiterated that the government will have to consider the health of its national carriers before making any decisions.
An Asean spokesman told The Straits Times in an e-mail response to queries that while member states are urged to ratify the Asean agreement "as soon as possible", the reality is that some "may take more time than others to ratify, as domestic procedures for ratification differ".
It does not, however, stop individual countries from liberalising their air links.
Singapore and Malaysia, for example, have decided to fully open the Singapore-Kuala Lumpur air route next month.
More flights are also progressively being added between Singapore and the East Malaysian states of Sabah and Sarawak.
Industry talk is that Penang is next.
Singapore carriers are also hoping that new opportunities will open up in the Philippines as well as in Indochina.
Jetstar Asia chief executive officer Chong Phit Lian said liberalisation had been good for consumers, adding that the airline looks forward to "official news of new points and opportunities that will be available within the region".
Her wish list? "More flights to and from Singapore and other points in Malaysia, as well as more rights to the Philippines and Indonesia."
The liberalisation between capital cities is the first step in a long-term plan to create the Asean Single Aviation Market by 2015.
When that happens, all carriers of member states will be able to criss-cross the region's skies without any restrictions. (By KARAMJIT KAUR/ The Straits Times/ ANN)