Jane Fonda's hair!

I loved this cut on her and, if you consider what work the character is doing in this film, it 'works' -- it's never mussed up by the sexscapades. Great cut -- she looks fantastic!!

The female "shag" haircut sported by Jane Fonda in Klute turned up on a few other actresses in the early 70s:

Donna Mills in "Play Misty for Me" in 1971
Jennifer Salt in "Play It Again Sam" in 1972.

And didn't Florence Henderson wear it for a few years on The Brady Bunch?

It was a style thing.

Here's a bad memory of youth from this then-young guy.

In the summer of 1968, Rosemary's Baby was released. The previously long-haired Mia Farrow wore her hair very short in that movie, as she did in real life during her short marriage to Frank Sinatra around this time(he DIVORCED her for doing Rosemary's Baby instead of a movie with him called The Detective.)

Anyway, we boys went back to school in September of 1968 after the summer and ALL the long-haired girls had cut their hair short like Mia Farrow. I couldn't stand it.

Soon came the seventies: long hair on women and girls again, parted down the middle. Shags. And at the end of the decade, flaired hair ala Farrah Fawcett.