The search has resumed on Wednesday morning for a light plane missing near Murwillumbah in north-eastern NSW, after a resident in the area reported seeing an aircraft simply "drop out of the sky".

The single-engine plane took off from Murwillumbah Airport about 10am on Tuesday with only the pilot, a 72-year-old man, on board.

About 15 minutes later, a witness reported seeing a plane in difficulty near Limpinwood, about 25 kilometres west of the airport.

"Did anyone see a plane fall out of the sky about 1 hour ago around Limpinwood?," the man posted online.