Fernandes said he came under pressure from Najib's government before the May 9 vote, causing him to issue a video enthusiastically crediting its policies for the success of the homegrown low-cost carrier.

But the Barisan Nasional coalition, which had ruled Malaysia for 61 years, suffered a humiliating defeat Wednesday at the hands of an opposition alliance led by his former mentor and ex-prime minister Mahathir Mohamad, 92.

Fernandes was strongly criticized online for the stunt endorsing Najib, who has been linked to a multi-billion-dollar corruption scandal involving Malaysian state fund 1MDB.

A photo showing Fernandes with Najib on board an AirAsia plane was widely circulated during the election campaign. That plane was painted in the blue colours of Najib's Barisan Nasional coalition.

Fernandes even changed the uniforms of AirAsia flight attendants from red to blue during that trip.

But in a video posted on his Facebook page Sunday, a somber-looking Fernandes apologized for his "grave error of judgement".

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"I'm sorry for what has gone on. I buckled at a crucial moment in our history," he said.

Fernandes said he had been under "tremendous" pressure from the then-government to sack popular former trade minister Rafidah Aziz, who is on the board of AirAsia's long-haul budget arm AirAsia X, because she was campaigning for the opposition.

Najib's government was also angry at him for adding extra flights to ferry people at low fares to their provinces so that they could cast their votes, and told him to cancel those flights, he said.

Fernandes said he "foolishly" thought that he could appease the government by coming up with the endorsement video as well as by repainting the plane and changing the flight attendants' uniforms.

"Under the intense pressure, I buckled. It wasn’t right, I'll forever regret it but it was a decision made at the spur of the moment," he said.

"I apologize again for the pain and the hurt I caused."

The new government slapped Najib with a travel ban on Saturday as speculation mounted he was about to flee the country in a possible bid to avoid prosecution over the 1MDB scandal. He has denied any wrongdoing.