A survey has found that more than 20 percent of airplane passengers had knowingly or unknowingly smuggled prohibited items past TSA checkpoints onto the aircraft, including at least 6 percent who boarded the plane while unintentionally carrying prohibited knives or other bladed objects.

Less than 1 percent claimed that they discovered belatedly that they had mistakenly traveled with firearms, ammunition or explosives.

The survey from Stratos Jet Charters Inc also found the most common items whisked past TSA agents on purpose were food and liquids. More than 3 percent admitted knowingly carrying bladed items past security, while 2.2 percent of female respondents and 3.7 percent of male respondents also acknowledged intentionally carrying prohibited drugs onto the aircraft.

In addition, it found that millennials were more likely than Gen Xers to disregard the rules for security screenings – nearly 1 in 5 said they’d knowingly traveled with unauthorized items, and women were more likely than men to end up having accidentally packed items they weren’t supposed to bring. In addition, respondents with postsecondary degrees were more likely to have unknowingly flown with these prohibited items.

Whether that was a self-defense item like pepper spray or even a pocketknife they forgot was tucked away at the bottom of their bag, nearly 29 percent of millennials said they got away with traveling with a few prohibited items.

Respondents who flew more than seven times a year were the most likely to both knowingly and unknowingly travel with things on the no-fly list. On average, these jet-setters admitted to knowingly packing banned items into their carry-on bags more than 16 times and unknowingly traveling with prohibited items nearly 11 times over the course of their lifetimes.

Men, married people, and those with postsecondary educational degrees also admitted to knowingly traveling with contraband between six and seven times, while millennials, those in relationships, and those without postsecondary degrees did it more than five times.