In present day, Steve McGarrett's mother Doris McGarrett is played by Christine Lahti. In flashbacks when Steve McGarrett is a boy, his mother really does look like a younger version of herself. The young Doris is played by Emma Lahti, Lahti's real-life daughter.
This episode marks the 150th episode of this show.
The title translates to "The Mother and Son".
The twin-prop plane at the private airstrip near Rabat, registration N45SA, is a Beech King Air C90 made in 1980. 507 of that variant were made, and over 3,100 of all types have been manufactured since it was first introduced in 1964. The most recent (2017) version is the C90GTx will set you back at least $3.4M.