Thai officials have acknowledged weaknesses that caused the United States to downgrade the safety rating of the country's aviation industry, saying its growth outpaced the ability of regulators to keep up.
The Federal Aviation Administration downgraded Thailand to a "category 2" rating, which means its civil aviation authority is deficient in one or more critical areas or that the country lacks laws and regulations needed to oversee airlines in line with international standards.
"Thailand does not comply with International Civil Aviation Organisation (ICAO) safety standards," the FAA statement said. It audited Thailand's civil aviation authority in July as part of its role in ensuring airlines that fly to the United States meet international standards.
Thai airlines will not be allowed to establish new services to the US under the category 2 status.
Thai transport minister Arkhom Termpittayapaisith said at a news conference on Wednesday that the main concerns among the 33 raised by the FAA were inadequate manpower and training and insufficient ability to vet the licensing of pilots in a timely manner.
"We had limitations in training our people to become inspectors," Mr Arkhom said. "We have 2,300 pilots and they have to renew their permits. We don't have enough people to inspect and grant the permits."
Thailand is one of the world's top tourist destinations, and its tourism industry accounts for about 7% of the country's economy.
Regulators in other countries are likely to be influenced by the FAA announcement, which could lead to measures against national flag carrier Thai Airways and other airlines.
Asked if he was concerned that the European Aviation Safety Agency would issue a downgrade similar to the FAA's later this month, Mr Arkhom acknowledged that the agencies operate by similar rules.
He said the effect of a European downgrade would be similar to that of the United States: existing flights to Europe would not be affected, but Thai airlines might not be able to increase the number of flights or change destinations or types of aircraft.
Thailand's military government ordered an overhaul of the civil aviation authority after ICAO made an initial negative assessment in March, but it could not meet a deadline for rectifying all the problems.
Arkhom said ICAO approved Thailand's corrective action plan and the two sides were working to implement it. He said Thai aviation authorities would focus on recertification of the 28 of Thailand's 41 airlines that operate international flights.
If the process goes according to plan, ICAO would be invited to make a new inspection before August 2016. If it is satisfied that the problems have been corrected, it could lift its rating immediately.
Thai Airways international president Charamporn Jotikasthira said the airline's business would be affected if any European restrictions on Thai flights were not lifted by 2017.
The airline, which is Thailand's flag carrier with 11 European destinations, has been ailing financially, and in October cut its last US route, to Los Angeles. It doesnot plan to add to its European flights in 2016.