Using delay, you need to put code in queue:
onRender: function () {
$('ul > li').each(function (i, element) {
$(element).delay(i * 50000).queue(function (next) {
$(this).toggleClass('fly-in-out');
next();
});
})
}
Or use a timeout:
onRender: function () {
$('ul > li').each(function (i, element) {
setTimeout(function () {
$(element).toggleClass('fly-in-out');
}, i * 50000);
})
}