I found it in Wikipedia:
"Mitch MacAfee (Morrow), a civil aeronautical engineer, while engaged in a radar test flight near the North Pole, spots an unidentified flying object. Three jet fighter aircraft are scrambled to pursue and identify the object but one aircraft goes missing. Officials are initially angry at MacAfee over the loss of a pilot and jet over what they believe to be a hoax.
When MacAfee and mathematician Sally Caldwell (Corday) fly back to New York, their aircraft also comes under attack by a UFO. With their pilot dead, they crash-land in the Adirondacks, where Pierre Broussard (Lou Merrill), a French-Canadian farmer, comes to their rescue. MacAfee's report is met with bewilderment and skepticism, but the military authorities are forced to take his story seriously after several more aircraft disappear. They discover that a gigantic bird "as big as a battleship", purported to come from an antimatter galaxy, is responsible for all the incidents. MacAfee, Caldwell, Dr. Karol Noymann (Edgar Barrier), Gen. Considine (Morris Ankrum), and Gen. Van Buskirk (Robert Shayne) work feverishly to develop a way to defeat the seemingly invincible creature.
The climactic showdown takes place in Manhattan, when the gigantic bird attacks both the Empire State Building and United Nations buildings. It is defeated by a special type of isotope, deployed from the tail gun position of a B-25 bomber aircraft, which successfully collapses the creature's antimatter shield and allows missiles to hit and kill the monster. The giant bird plummets into the Atlantic Ocean outside New York, and the last sight of it is a claw sinking beneath the ocean."
https://en.wikipedia.org/wiki/The_Giant_Claw
In my opinion, this film is much better than many new ones, terrible monster is spreading terror everywhere, even new technology, can't stop this monster, but US Air Forces never surrender... Fantastic B-W pictures and houses, trains and cars, are flying in air like toys, people are really scared, have good time :)