Yes Hela, both can be used, although with a slight difference of meaning.
Majority of +plural : you focus on the individuals belonging to the group :
The majority of people drink alcohol : that's the individuals who drink 1+1+1+1
The majority elects our candidate: the group as a whole opts for this election.
....The majority of people is against isolationism
a majority of people go to the cinema. That is not the decision of a whole but the common tendency of individuals belonging to a definite group.
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