With Kingfisher Airlines defaulting on lease rentals of around Rs.1,000 crore, the lessors had taken back 34 aircraft, sources said here on Tuesday even as the company maintained that it had returned the aircraft voluntarily. Besides, another 15 aircraft of the company were also aground due to want of spares. The airline was now left with only 15 planes to carry out its operations, they said. The airline, however, said it had returned these aircraft voluntarily.