Snippet to hide Flat rate if cart amount is more than specified amount else hide Free Shipping. If the product comes with other products add the flat rate to ups and hide other rates. PluginHive Plugins - https://www.pluginhive.com/plugins/

functions.php

/**
 * Snippet to hide Flat rate if cart amount is more than specified amount else hide Free  Shipping. If the product comes with other products add the flat rate to ups and hide other rates.
 * Created at : 20 Sep 2018
 * Updated at : 28 Sep 2018
 * PluginHive Plugins : https://www.pluginhive.com/plugins/
 * Gist Link : https://gist.github.com/varun-pluginhive/2cea63276a98c1869328c1743993e4ee
 */
if( ! empty('ph_skip_shipping_method_based_on_shipping_class') ) {
	function ph_skip_shipping_method_based_on_shipping_class( $shipping_costs, $package ) {

		$thresold_order_amount = 1000;			// Order Amount above which flat rate needs to be hidden below that Free Shipping needs to be hidden
		$flat_or_free_shipping_class = array('shoe');	// Shipping Class of Flat Rate or Free Shipping


		$only_flat_or_free_shipping =false;
		$ups_only = false;
		foreach( $package['contents'] as $line_item) {
			$shipping_class = $line_item['data']->get_shipping_class();
			
			if( empty($shipping_class) ) {
				$ups_only = true;
				continue;
			}
			elseif( in_array($shipping_class, $flat_or_free_shipping_class) ) {
				$only_flat_or_free_shipping = true;
			}
			else{
				$ups_only = true;
			}
		}

		$cost_to_add = 0;
		if( $ups_only && $only_flat_or_free_shipping ) {
			foreach( $shipping_costs as $key=> $shipping_cost) {
				$shipping_method_id = $shipping_cost->get_method_id();
				if( $shipping_method_id == 'flat_rate' ) {
					$cost_to_add = (double) $shipping_cost->get_cost();
					unset( $shipping_costs[$key]);
				}
				elseif( $shipping_method_id == 'free_shipping' ) {
					unset( $shipping_costs[$key]);
				}
			}

			if( ! empty($cost_to_add) ) {
				foreach( $shipping_costs as &$shipping_cost) {
					$shipping_cost->set_cost( $cost_to_add + (double) $shipping_cost->get_cost() );
				}
			}
		}
		elseif( $ups_only ) {
			foreach( $shipping_costs as $key=> $shipping_cost) {
				$shipping_method_id = $shipping_cost->get_method_id();
				if( $shipping_method_id == 'flat_rate' || $shipping_method_id == 'free_shipping' ) {
					unset( $shipping_costs[$key]);
				}
			}
		}
		elseif( $only_flat_or_free_shipping ) {
			$cart_cost = (double) $package['cart_subtotal'];
			foreach( $shipping_costs as $key=>$shipping_cost) {
				$shipping_method_id = $shipping_cost->get_method_id();
				if( $cart_cost > $thresold_order_amount && $shipping_method_id == 'flat_rate') {
					unset($shipping_costs[$key]);
				}
				elseif( $cart_cost <= $thresold_order_amount && $shipping_method_id == 'free_shipping'){
					unset($shipping_costs[$key]);
				}
			}
		}

		return $shipping_costs;
	}

	add_filter( 'woocommerce_package_rates', 'ph_skip_shipping_method_based_on_shipping_class', 10, 2 );
}