[{_id:ObjectId("5a934e000102030405000000"),Vehicles:[{Manufacturer:"Chevrolet",color:"blue"},{Manufacturer:"Nissan",color:"blue"},{Manufacturer:"Hyundai",color:"blue"},{Manufacturer:"Nissan",color:"blue"},{Manufacturer:"FORD",color:"blue"},{Manufacturer:"FORD",color:"blue"}],}]

db.collection.aggregate([{"$set":{"unfiltered_makes":{"$function":{/** generate histogram of manufacturers and format output*/"body":"function(makes) {const m = new Object();makes.forEach((elem) => {m[elem.Manufacturer] = m[elem.Manufacturer] + 1 || 1});return Object.entries(m).map(([make, count]) => {return {'_id':make, 'count':count}})}","args":["$Vehicles"],"lang":"js"}}}},{"$project":{"_id":0,"unfiltered_makes":1,"makes":{"$filter":{"input":"$unfiltered_makes","as":"make","cond":{"$eq":["$$make._id",/** your search "Manufacturer" goes here*/"FORD"]}}}}}])