One annoyance of ordering items from the internet is waiting for delivery. That’s why many companies are set on making sure you get your items as quickly as possible — like Amazon Prime’s free two-day shipping.

But shipping, especially fast, comes at an environmental cost. Previous studies have shown that moving goods by conventional aircraft is four times more carbon-intensive than by truck, which is 10 times more carbon-intensive than rail. Since many companies including Amazon, UPS, Bo