A woman carried a nine-inch serrated knife on a flight from Portugal without the implement being detected.
Mrs Mallon landed at Exeter Airport
Helen Mallon, 43, from Bath, passed through X-ray machines, metal detectors and security guards at Faro with the bread knife in her bag.
Mrs Mallon said she forgot she had the gift in her hand luggage and flew with it to Exeter Airport.
Faro airport said an investigation was under way to find out how Mrs Mallon managed to pass through security.
Mrs Mallon was returning from a week-long holiday in Portugal with her partner and children.
She said: "It was not until after checking in the luggage and going through the scanners before boarding that plane that I thought 'Oh my God, I have still got
She decided not to tell cabin staff, but added: "Thank God I am not a terrorist.
"They say it is high security these days, but it is obviously not as high as we imagine."
Faro airport director Antonio Mendes said: "We have become aware of the issue and we have started to make
inquiries to find out what has happened.
"What we need to know is how the lady boarded the flight with the knife and who was responsible to check and verify at security.
"We will also be raising the issue with the security company and those individuals involved will be made to go for extra training."
Exeter Airport told the BBC it knew nothing about the incident.