IT was the most inspiring voyage of Arlo Guthrie's itinerant music career, but a lot of the details are a bit of a blur now, like so much of the late 1960s. "I was flying from London to L.A. I don't know what airline it was. It was around 1968 -- well, I know it was after 1965. It was between 1966 and 1968. I was like 18 or 19. I'm sorry. It was a long time ago." The one thing Guthrie absolutely remembers is the turbulence.

"It was one of those bumpy flights where the whole plane just drops and you feel like you're in a car that just bottomed out on the road."

The ride was so rough that stewardesses were dropping chicken dinners off their trays. Passenger Guthrie had another reason for jangled nerves; his London friends had sent the young American home with some gifts and, after takeoff, he opened one and found some contraband inside that left him in a smuggler's sweat and, later, inspired a song.

Coming in from London from over the pole

Flying in a big airliner

Chickens flying everywhere around the plane

Could we ever feel much finer?

Coming into Los Angeles, bringing in a couple of keys

Don't touch my bags if you please

Mister Customs Man

The son of Woody Guthrie was already a counterculture star thanks to the 1967 folk epic "Alice's Restaurant Massacree," and he only added to his rep as a troubadour prodigy when he performed "Coming Into Los Angeles" at Woodstock in 1969.

In Michael Wadleigh's era-defining festival documentary, the tune plays with a montage of shaggy fans passing around joints, and Guthrie's song instantly became a generation's soundtrack for blowing smoke in the face of authority. For the record, Guthrie exaggerated the size of his stash. "I'm a teller of tall tales; in this case, the reality wasn't nearly that tall."

The song popped up memorably in the 1971 post-apocalyptic L.A. film "The Omega Man," but it was widely banned at radio for (of all things) a veiled sex reference to a passenger leering at a "hip woman" and "thinking that he's already made her."

Limited airplay or not, the song still echoes. In 2003, Guthrie was at Boston's Logan International Airport when he felt the stares of two federal agents with dour expressions and plastic earpieces. "Now, people like me, we have a chemical reaction to people like that. One of them walks over and says, 'You Guthrie?' I said, 'Yeah,' and he looks at my bag and goes, 'You got, uh, a couple keys in there?' Then he just smiled and asked for an autograph. Hah! The times have changed, haven't they?"

geoff.boucher@latimes.com