[{"_id":"1","name":"qwe","password":"pw","carPolicies":[{"policy":{"agent":"47"}}],"paPolicies":[{"policy":{"agent":"47"}}]},{"_id":"2","name":"rty","password":"wp","carPolicies":[{"policy":{"agent":"47"}},],"paPolicies":[{"policy":{"agent":"47"}},{"policy":{"agent":"99"}}]}]

db.collection.aggregate([{$match:{$or:[{"carPolicies.policy.agent":"47"},{"paPolicies.policy.agent":"47"}]}},{$project:{policy:{$filter:{input:{$concatArrays:["$carPolicies.policy","$paPolicies.policy"]},as:"police",cond:{$eq:["$$police.agent","47"]}}}}},{$unwind:"$policy"},{$project:{_id:0,policy:["$policy"]}}])