Dangling from my seat-back pocket was a long blonde clip-in extension, the one that had been draped over my lunch for an hour. It was clipped neatly in place with the little binder clip I keep in my purse for crossword pages. When she bent down for the money, I’d simply fastened its ends. When she sat up, it stayed behind. Her own hair underneath was half that length.

“She stole my hair!” she shrieked. The flight attendant looked at the extension, then at me. “Ma’am, did you take her hair?” “No,” I said calmly. “It came over the seat by itself. I just stopped it.” The attendant turned to the blonde. “And is that fifty-dollar bill yours?” “Yes!” she snapped. “Then you won’t mind reading what’s written on it,” I said.

She pulled the bill out of her purse and unfolded it. In blue ink across the margin, in my neat schoolteacher handwriting, it said: Property of Dorothy, Seat 23C. Keep your hair to yourself. I had written it twenty minutes earlier, right after the second time her hair landed in my coffee. Even the flight attendant read it twice. The teenage boy across the aisle lost it completely. Half the cabin started laughing with him.

The flight attendant pressed her lips together to keep from smiling. She took the bill, handed it back to me, and told the blonde that taking money that wasn’t hers, after being warned twice about her hair, was enough for a formal report. The woman across the aisle actually applauded. Then the attendant unclipped the extension from my seat pocket and handed it back to its owner, at arm’s length, like evidence.

The blonde was moved to an empty middle seat in the last row, between two very large men who had both been watching. Her hair stayed firmly on her side for the rest of the flight. At baggage claim, she walked past me without a word, the extension stuffed into her tote bag. The teenage boy gave me a thumbs-up as we deplaned. His name was Tyler. I gave him a mint. His mother, meanwhile, bought me a fresh coffee.

At my granddaughter’s graduation the next day, I told the story at dinner. She laughed so hard she cried, then asked to keep the fifty-dollar bill. It’s framed in her new apartment now, my handwriting and all. Her friends asked to meet me. I’m apparently a legend at her university now. Underneath the frame, she taped a little card. Grandma’s rules: be kind, be patient, and if that doesn’t work, bring a binder clip.