Factory of union type without type casting

abstract class Passenger {
    passengerKey: string;
}

class PassengerAdult extends Passenger {
    adultField: string;
}

class PassengerInfant extends Passenger {
    infantField: string;
}

class PassengerFactory {
    static createPassenger(isInfant: boolean): PassengerAdult | PassengerInfant {
        if (isInfant) {
            return new PassengerInfant();
        }

        return new PassengerAdult();
    }
}

const passengerInfant: PassengerInfant = PassengerFactory.createPassenger(true); 

I get an error that

Type 'PassengerAdult | PassengerInfant' is not assignable to type 'PassengerInfant'. Type 'PassengerAdult' is not assignable to type 'PassengerInfant'. Property 'infantField' is missing in type 'PassengerAdult'.

Can I in some way force typescript to understand what he's returning inside createPassenger method? I know that in the call line I'd cast the result like

const passengerInfant: PassengerInfant = <PassengerInfant>PassengengerFactory...

but i'd like to avoid that.