But there’s a good reason for this proposed window-killing—sticking windows onto the sides of planes means you have to bulk up the fuselage, which makes planes heavier, and bigger gas guzzlers. There’s a reason cargo planes don’t have windows.

CPI estimates that for every 1 percent of weight reduction, planes see a 0.75 percent fuel savings. And that’s a big deal. Airlines burn hundreds of millions of gallons of fuel every month—easily the industry’s biggest expense. Cutting back the weight of a given plane by even 5 percent would have huge ramifications for an airline’s profit margins, and the cost of airfare.

In CPI’s design, the firm imagines replacing windows with low-energy OLEDs (organic light-emitting diodes) that could use cameras to realistically broadcast the outside environment in a panoramic view that could be toggled on or off by the passengers.