Thanks for the link - the shot of those carriers was awe-inspiring (I’m assuming they were pretty confident no concentration of Japanese air power was likely to come down on them there).
Except for the evening of evening of March 11, 1945, when the fleet was there. That day, the Japanese launched Operation Tan No. 2, which was a kamikaze mission by 24 long range twin-engine bombers, each carrying a 1700 pound bomb. Launched from an airfield on southern Kyushu, Ulithi was at the limit of their one-way range. The plan was to attack and cripple the American fleet at anchor.
For various reasons, of the 24 planes launched, only 2 made it to Ulithi, and achieved complete surprise. One crashed on the island, causing no damage. However, the other one struck USS Randolph, CV-15, on her aft flight/hangar deck. The ship was sufficiently damaged that she missed the operations against airfields on the home islands, which were preparatory to the invasion of Okinawa.
So Ulithi wasn't completely safe.