Bangkok is scrambling to undo bans on extra flights offered by Thai-registered airlines after the International Civil Aviation Organisation (ICAO) flagged significant safety concerns about local aviation standards.
The Thai authorities are in talks with Japan for a reprieve pending a shake-up in aviation regulation in the country.
Singapore's civil aviation authority, meanwhile, says it has increased surveillance and inspections of Thai carriers' aircraft operations in the Republic.
"Thus far, we have not imposed any restrictions on Thai carriers," it said in a statement. But it would "closely monitor developments" and "consider further measures, as necessary, to ensure that safety is not compromised".
Thailand's military government has been under pressure to improve oversight of its aviation sector after news emerged that it had failed an ICAO audit in January.
Thailand is a major aviation hub, with more than 40 airlines based in the country, ranging from the state giant Thai Airways to smaller domestic outfits such as Kan Air and private carriers that include Orient Thai.
It is also the base for Nok-Scoot, a medium- to long-haul carrier created through a joint venture between Singapore Airlines' wholly owned subsidiary Scoot and Thai budget airline Nok Air.
Last year, 46.4 million passengers passed through Bangkok's Suvarnabhumi Airport.
Japan, China and South Korea have reportedly stopped granting permission for additional flights by Thai carriers.
Nearly 120,000 passengers wanting to travel to Japan on charter flights could have been affected by the bans this month and next, a busy time for Thai travellers, Reuters quoted a Bangkok official as saying on Tuesday.
Thailand's Department of Civil Aviation director-general Somchai Piputwat told The Straits Times that ICAO had flagged outdated laws and inadequate personnel training as areas found wanting. These had nothing to do with the safety of the country's airlines, he stressed.
But government assurances about air safety were undercut by news that an Orient Thai plane had plunged mid-flight over China last Saturday and was forced to make an emergency landing.
The airline issued a statement on Tuesday saying its flight from Thailand's resort island of Phuket to China's Chengdu city carrying 132 passengers "landed as normal" in Kunming city's airport.
"The change in air pressure in the cabin caused the oxygen masks to fall" from their overhead compartments, it said, adding that no one was injured. "There were no shocks and surprises like it was reported in the news."
It did not explain why there was a change in cabin pressure.
News and social media reports in China alleged engine failure and claimed some passengers suffered nosebleeds and inflammation of the eardrum as a result of the sudden drop in altitude.
The Thai government now plans to start a new civil aviation regulatory body to handle airline licensing. Prime Minister Prayut Chan-ocha has said he will use special powers granted in the Constitution drawn up after the coup last May to bypass lengthy procedures and improve safety.
This article was first published on April 3, 2015.
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