Yadav came out with his riposte half-mockingly, in an obvious attempt to get back at the senior BJP leader, whose remarks have been seen as an attempt to create a rift between RJD, the largest constituent of the ruling Mahagathbandhan in the state, and Chief Minister Nitish Kumar's JD(U).
Notably, the Mahagathbandhan formed its government last year when Kumar joined it, snapping ties with the BJP.
The JD(U) leader, who has broken up and realigned with BJP more than once, now claims that he is out of NDA for good and was looking forward to pass on the mantle to Yadav.
However, when Yadav was asked about the claim of Singh, he replied: "It is a senseless and imaginary claim on the part of Giriraj Singh who was seated next to me (on the plane). My father was on another side".
He added that the brief exchange between Prasad and Singh centred around the BJP leader's desire to have a feast of "mutton" hosted by the RJD president.
According to Yadav, his father replied with trademark wit, saying "But you are intent on only jhatka meat. We will try to arrange for it and then let you know".
The allusion was to a recent appeal by Singh in his Lok Sabha constituency of Begusarai that "Hindus" give up heating "halal" meat and stick to "jhatka", a term used for slaughter by a single blow of the blade.
Yadav sought to twist the knife, as he added: "For the most part, Giriraj Singh kept talking to me, which I hesitate to reveal in public. He was obviously worried about his own prospects. The way Union ministers were pushed into states during recent assembly polls, seems to have left him rattled".
"Giriraj Singh is extremely worried as to whether he will be considered for a ticket in the upcoming Lok Sabha polls. He also confided in me that in the Union government, none of the ministers enjoyed real power. Only one or two persons were calling the shots", added the RJD leader.
With an air of mischief, he said, "But we grant him the right to say in public whatever suits his politics".
No response has come so far from Singh whom Yadav, nearly four decades his junior, seems to have caught on the wrong foot.