Five people were on board the helicopter, two of them children.
The Balearic Islands government said on Twitter they were likely German nationals.
Two adult Spaniards were on the small plane, it added.
The crash happened above the village of Inca at about 1.30pm local time.
Spanish news agency Europa Press quoted local officials as saying the aircraft had crashed into a farm field.
Further debris was later pictured on a road in Inca as locals gathered round.
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Spanish caretaker prime minister Pedro Sanchez tweeted of the crash: "My solidarity and affection for the families of the victims who have lost their lives is this tragic accident, including a minor."
It comes after two people died in a light aircraft crash near near Henley-on-Thames in the UK on Saturday.
This page is being updated.