Were interstate highways designed with one in every five miles straight for use as emergency airstrips?

The Federal Highway Administration confirms that such a claim, which has circulated on social media since at least 2000, is not true.

The highway administration says on its webpage titled "Interstate Highway System - The Myths":

"This myth is widespread on the Internet and in reference sources, but has no basis in law, regulation, design manual -- or fact. Airplanes occasionally land on Interstates when no alternative is available in an emergency, not because the Interstates are designed for that purpose."

A 2000 article by an information specialist with the highway administration said Congress considered including a flight strip program in a 1944 law that authorized a "National System of Interstate Highways" -- but the 1944 act as finalized did not include the flight-strip program.