Most airborne land bird

The most aerial bird is the common swift (Apus apus), which remains airborne for two to four years, during which time it sleeps, drinks, eats and even mates on the wing. It has been calculated that a young swift completes a non-stop flight of 500,000 km 310,000 miles between fledging and its first landing at a potential nesting site two years later. Unlike swallows and martins, the bird never lands on ground or perches on wires, and indeed spends almost all it's life on the wing.