DCA director-general Woradej Harnprasert issued the warning as he "advised" the privately owned Thai airline to suspend flights until it resolves problems related to unpaid bills for airport charges and jet fuel, amounting to more than 10 million baht.
"We won't be reluctant to cancel the AOL [Air Operator License] if the errors are repeated," he told the Bangkok Post, adding that the incident damaged the country's reputation.
The DCA's warning came as PC Air struggled to ferry back scores of Thais stranded at Incheon International Airport back to Bangkok yesterday.
In Bangkok yesterday, 32 Thais who bought South Korean tour packages with flights on PC Air, filed complaints with the Crime Suppression Division (CSD) seeking compensation from the carrier for not providing them the services they paid for.
Some 400 Thais were left stranded in Incheon on Tuesday following a financial row between the airline and its Korean sales agent Skyjet, which resulted in PC Air's sole aircraft, an Airbus 310-222 with 200 seats, being refused permission to take off from Incheon.
Speaking from Incheon yesterday, PC Air president Peter Chan said he was on the spot to clear up the problems as a matter of priority to get all remaining stranded passengers back to Thailand as soon as possible.
PC Air has not yet announced whether it would suspend its regular flights from Bangkok to Incheon and Hong Kong, as suggested by the DCA yesterday. Mr Woradej said it is up to PC Air to decide whether to follow the DCA's advice to suspend its operations for the time being.
He also said DCA could not take legal action against PC Air on this matter because its authority did not cover international chartered flights and stranded passengers would have to file civil lawsuits against the airline by themselves.
He promised that the DCA was ready to provide complainants with information about the airline.
Deputy Transport Minister Chatchart Sithipan said that if PC Air was shown to be guilty of violating a law or failure to comply with passenger service regulations, its licence would be terminated.
A chartered airline licence must be renewed on a monthly basis and the licence of PC Air will expire on Oct 31.
PC Air reportedly plans to add two used Boeing 767s, the wide-body twinjet capable of carrying more than 200 passengers, to its operations starting in December this year.
Tourists and tour agents who waited in vain for their PC Air flight to South Korea on Tuesday night filed their complaints with the CSD yesterday.
A woman who was among the complainants said she bought a five-day tour package to South Korea from a travel agent but the airline could not serve her on Tuesday night.
She and other tourists, including those from other provinces, were told that PC Air and their tour agents would work out solutions for them.
Meanwhile, Pongsak Artkham, 32, filed a complaint with the CSD yesterday against Global Asia Travelling Co, owned by Chao Lophetrat, 27, and his wife Chanya Yupalak.
He accused them of fraud because they postponed an Oct 22-26 trip to South Korea which he and his family had booked through them.
The firm charged each of the five-member family 13,900 baht for the trip, he said. The family paid up but learned later that the couple had also postponed the trips of over 100 other clients and had been accused in other fraud cases.