Patel on Tuesday appeared before the ED for the second consecutive day in connection with the multi-crore airline slot allocation scam case. He was questioned for over nine hours on Tuesday.
The NCP leader is being questioned for his alleged involvement in awarding favourable air traffic rights to foreign airlines that caused losses to national carrier Air India.
On Monday, Patel was questioned for nearly eight hours by the ED. He refused to answer media queries on what transpired at the probe office.
The name of Patel, who was the civil aviation minister between 2004 and 2011, surfaced in a charge sheet filed by the ED against corporate lobbyist Deepak Talwar on March 30.
The agency had in its charge sheet said that Talwar, who is currently in judicial custody, allegedly acted as a middleman to favour foreign private airlines. It also said that Talwar was in regular touch with the former Aviation Minister.