I would theorize it is most likely an hour but could be up to a few weeks. This is based how much the plant has aged on the trip from Earth to the Axiom and how much the people aged on the trip from the Axiom to Earth. Many orbiting satellites and space junk are visible in the atmosphere. In 2805, Earth is covered in garbage due to decades of mass consumerism facilitated by the megacorporation Buy n Large.

The Earth in 2805 AD. EVE, still in hibernation mode, is taken away to the ship's commander.
Wikipedia provides answers:. Earth is the location of WALL•E's home in the film, WALL•E.. WALL•E. Several days later, the mother ship returns and collects EVE. Before 2105 AD: During the middle 21st century, the Buy n Large corporation assumed control of the planet's entire economy, including various world governments.. 2105 AD: The population had reached to around 200 billion. E character was the last of the thoughts discussed at the now legendary 1994 lunch meeting where he, John Lasseter, Pete Docter, and Joe Ranft came up with ideas that were central to many of Pixar's most iconic films. WALL-E hitches a ride on the ship, which returns to the Axiom several light years away from Earth.
EVE and WALL-E are examined in the landing bay.