I haven't read the story, so I don't know the exact statement this character gave.

Is the character saying that he flew "to France" or did he say something like "to French territory"?

France held on to Djibouti as a colonial holding until 1977, and in 1974 it would have been called the "French territory of the Afars and Issas". An Ethiopian pilot taking off in Ethiopia or Eritrea (part of Ethiopia at the time) might be able to defect to Djibouti fairly trivially, since that territory shares a land border with Ethiopia.

If the character says "and I landed my plane in Toulon" or something else to clearly indicate that they were crossing the mediterranean and defecting to metropolitan France....that seems much much less likely, given the issue of crossing multiple countries airspace, and the issue of fuel capacity.

To your second question, there are a handful of examples of Ethiopian pilots defecting to Sudan, Somalia, Djibouti, and Yemen. However, all the examples that I know of occurred from the late 1970s onward.