This is what LaGuardia Airport could look like by 2021 — a far cry from the current dilapidated “Third World” facility.

Manhattan design firm Neoscape created renderings for the advocacy group Global Gateway Alliance that showcase a modern-looking airport with an airy main terminal, based on parameters established by the Port Authority.

The 1.3-million-square-foot space is one-third larger than the current central terminal.

LaGuardia currently handles double the amount of passengers for which it was built. About 12 million people travel through the airport each year, and the number is expected to rise to 18 million by 2030.

The new airport design leaves space for a future direct subway line.

“This comprehensive vision integrates a modern, efficient and innovative design, including the striking all-glass facade, into La Guardia’s main terminal,” said Joseph Sitt, chairman of the Global Gateway Alliance.

The PA will complete the LaGuardia makeover by 2021. It is expected to pick a firm in the next few weeks for the project.

In February, Vice President Joe Biden said if he blindfolded someone and took him to LaGuardia, he’d think he was in “some Third World country.”

LaGuardia workers who hail from countries around the world then told The Post it’s actually worse than that.