This is a Skywalker Sound sound effect. It is nearly identical to HORN, NAVAL - NAVAL SHIPYARD SIREN or may be a cleaner recording of that, in which case it actually would be a 20th Century Fox sound effect. It sounds identical to Elektra Records, Air Raid Alert from the Authentic Sound Effects Volume 3. Links: https://soundeffects.fandom.com/wiki/SKYWALKER,_SIREN_-_AIR_RAID_SIREN#Audio_Samples