To what extent did the American Civil Rights movement influence Australia's Freedom Rides and how are they similar and different?

The US Civil Rights movement had a very large influence on the Freedom Rides program in Australia, and it's quite possible that Freedom Rides would not have existed otherwise.

In 1964, a protest at the University in Sydney against racial discrimination in the US was held in solidarity with similar protests going on in the US. But one of the most common critical responses to that protest was that Australian protesters should "look to their own backyard"---that is, that racial discrimination in Australia against Aborigine people was just as bad as racial discrimination against African-American people in the US.

A group of University of Sydney students who were at that protest took it upon themselves to determine whether this was really true, and if so, what could be done about it; so they went on a fact-finding mission across New South Wales, documenting the treatment of Aborigine people in several cities both in writing, in photographs, and on video. This ultimately became the Freedom Rides.

The Freedom Rises raised a great deal of awareness of discrimination against Aborigines and helped expand a new civil rights movement in Australia, which modeled itself quite explicitly after the civil rights movement in the US.

One difference between the two is that it took Australia longer to make major headway in their civil rights movement; while the Civil Rights Act was passed in the US in 1964, the Racial Discrimination Act was not passed in Australia until 1975, over a decade later.

There is another major difference that I think is worth pointing out: Aborigine people are indigenous to Australia. In this respect they are more like Native Americans in the US, who to this day are treated a good deal worse than other racial minorities. While the US civil rights movement did include them in theory, in practice this was not always the case, and the focus was often quite strongly on rights for African-Americans as opposed to other racial minorities such as Asians and Native Americans. Conversely, African-Americans were brought to the US from Africa by the Atlantic slave trade. While slavery did exist in Australia, there was never a very large slave population in Australia the way there was in the US. These different historical causes of racial injustice led to different kinds of oppression and different responses to that oppression.