Aliens have not been in contact with either the U.S. or Israel for any length of time.
A former Israeli space security chief, Haim Eshed, has claimed that extraterrestrials have been in contact with the U.S. and Israel. He has claimed that the aliens are from something called the Galactic Federation.
In an interview with Israel's newspaper Yediot Ahronot, Eshed stated that aliens were curious about humanity, and were seeking to “understand” life on earth. He claimed that contracts had been signed between the alien representatives and American astronauts, and these contracts allowed them to carry out experiments together in an "underground base in the depths of Mars".
He added that President Donald Trump was aware of the aliens' existence, but the Galactic Federation asked him not to reveal the truth as this could cause mass hysteria. He stated that the Galactic Federation believed that humanity still needed to come to terms with extraterrestrial objects.
Haim Eshed’s claims are not true. There is no evidence of a Galactic Federation, and humanity has not yet found signs of extraterrestrial life. According to NBC News, a spokesperson for NASA has said that “one of the agency's key goals [is] the search for life in the universe but that it [has] yet to find signs of extraterrestrial life.”