Would anyone know a way to update multiple marker positions live using LeafletJS?

I came across this post: Updating Leaflet Marker Position Every x Seconds with JSON, which works perfect for a single marker, but when I try to add more than one marker, the map beings to lag bad and the markers don't clear they just replicate.

function update_position() {
    $.getJSON('https://opensky-network.org/api/states/all', function(data) {
        var planes = data.states
        for(let i = 0; i < planes.length; i++){
            plane = planes[i]
            lat = plane[6]
            lon = plane[5]
            csfilter = plane[1].substring(0,3);
            if(csfilter == "EIN"){
                if(!aircraft){
                    //var live_position = [[plane[1], plane[6], plane[5]]]
                    aircraft = L.marker([lat,lon]).bindPopup("I am "+plane[1]).addTo(mymap);
                }
            }
        }
        aircraft.setLatLng([lat,lon]).update();
        setTimeout(update_position, 10000);
    });
}
update_position();

Would anyone assist or point me in the right direction for where I am going wrong?