Yair Netanyahu, son of Israeli Prime Minister Binyamin Netanyahu, joined his father's trip to Washington and will speak to American Israel Public Affairs Committee (AIPAC) youth.
The two left for Washington late on Saturday night, and the Prime Minister is expected to return on Thursday.
The Prime Minister's office emphasized that Yair Netanyahu's expenses came out of the family's private pocket.
"I am speaking to AIPAC youth," Yair tweeted. "I'm paying my own flight expenses, so the State only gains (since the flight would cost the same amount with me or without me)."
"On the other hand, former Prime Minister [Ariel] Sharon's sons joined him on every trip. And they had no official job. And they certainly didn't pay out of pocket."