[{"SessionKey":"172e3b6b-509e-4ef3-950c-0c1dc5c83bab","Query":{"Date":"2020-03-04"},"Flights":[{"LegId":"13235","PricingOptions":[{"Agents":[1963108],"Price":61763.64},{"Agents":[4035868],"Price":62395.83}]},{"LegId":"13236","PricingOptions":[{"Agents":[2915951],"Price":37188.0}]}]}]

db.collection.aggregate([{"$match":{"Query.Date":"2020-03-04"}},{$unwind:"$Flights"},{$addFields:{"Flights.LegId":{$reduce:{input:"$Flights.PricingOptions",initialValue:0,in:{$add:["$$value","$$this.Price"]}}}}},{$match:{"Flights.LegId":{$gt:1}}},{$group:{_id:"$_id",SessionKey:{$first:"$SessionKey"},Query:{$first:"$Query"},Flights:{$push:"$Flights"}}}])